A petlja je programska kontrolna struktura koja vam omogućuje izvršavanje a blok koda na neodređeno vrijeme ako je ispunjen određeni uvjet. Petlje se koriste za izvršavanje aktivnosti koje se ponavljaju i povećanje performansi programiranja. U programskom jeziku C postoji više petlji, od kojih je jedna 'do-while' petlja .
A 'do-while' petlja je oblik a petlja u C koji prvo izvršava blok koda, nakon čega slijedi uvjet. Ako je stanje pravi , the petlja nastavlja teći; inače, prestaje. Međutim, je li stanje izvorno pravi , osigurava da se blok koda izvodi barem jednom.
do while sintaksa petlje
Sintaksa do-while petlje jezika C je dana u nastavku:
do{ //code to be executed }while(condition); Komponente su podijeljene na sljedeće:
burak ozcivit
- The učiniti ključnu riječ označava početak Petlje.
- The blok koda unutar vitičaste zagrade {} je tijelo petlje koje sadrži kod koji želite ponoviti.
- The dok ključna riječ slijedi uvjet u zagradama (). Nakon pokretanja bloka koda, ovaj se uvjet provjerava. Ako je stanje pravi , petlja se nastavlja else, the završeci petlje .
Rad petlje do while u C-u
Pogledajmo primjer kako a do-while petlja radi u C-u. U ovom primjeru ćemo napisati jednostavan program koji postavlja pitanja korisniku za a lozinka i nastavlja pitati dok se ne unese prava lozinka.
Primjer:
#include #include int main() { char password[] = 'secret'; char input[20]; do { printf('Enter the password: '); scanf('%s', input); } while (strcmp(input, password) != 0); printf('Access granted!
'); return 0; } Program radi na sljedeći način:
- Uključene su sljedeće datoteke zaglavlja: za standard ulazni i izlaz rutine i za niz funkcije manipulacije .
- Ispravna lozinka definirana je kao a niz znakova (char lozinka[]) s vrijednošću 'tajna'
- Nakon toga definiramo još jedan unos niza znakova za pohranjivanje korisničkog unosa.
- The učiniti ključnu riječ označava da je blok koda uključen unutar petlja će se izvesti najmanje jednom.
- Koristiti funkcija printf(). , prikazujemo upit koji od korisnika traži da unese svoju lozinku unutar petlje.
- Zatim čitamo korisnički unos koristiti funkcija scanf(). i pohranite ga u ulazni niz .
- Nakon čitanja ulazni , koristimo se funkcija strcmp(). za usporedbu unosa s ispravnom lozinkom. Ako su žice jednak, the funkcija strcmp vraća 0. Dakle, nastavljamo s petljom sve dok unos i lozinka nisu jednaki.
- Jednom ispravna lozinka se unese, petlja završava i ispisujemo 'Pristup odobren!' koristiti funkcija printf(). .
- Nakon toga, program vraća 0 kako bi označio uspješno izvršenje.
Izlaz:
Prođimo kroz mogući scenarij:
Enter the password: 123 Enter the password: abc Enter the password: secret Access Granted!
Obrazloženje:
U ovom primjeru, korisnik inicijalno unosi krive lozinke, '123' i 'abc' . Petlja od korisnika traži ispravnu lozinku 'tajna' je upisano. Nakon što se unese ispravna lozinka, petlja se prekida, a 'Pristup odobren!' prikazuje se poruka.
Primjer do while petlje u C-u:
Primjer 1:
Evo jednostavnog primjera a 'do-while' petlja u C koji ispisuje brojeve od 1 do 5:
#include int main() { inti = 1; do { printf('%d
', i); i++; } while (i<= 5); return 0; } < pre> <p> <strong>Output:</strong> </p> <pre> 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the <strong> <em>code block</em> </strong> within the do loop will be executed at least once, printing numbers from <strong> <em>1 to 5</em> </strong> . After each iteration, the <strong> <em>i value</em> </strong> is incremented, and the condition <strong> <em>i<= 5< em> </=></em></strong> is checked. If the condition is still true, the loop continues; otherwise, it terminates.</p> <p> <strong>Example 2:</strong> </p> <p>Program to print table for the given number using do while Loop</p> <pre> #include intmain(){ inti=1,number=0; printf('Enter a number: '); scanf('%d',&number); do{ printf('%d
',(number*i)); i++; }while(i<=10); return 0; } < pre> <p> <strong>Output:</strong> </p> <pre> Enter a number: 5 5 10 15 20 25 30 35 40 45 50 Enter a number: 10 10 20 30 40 50 60 70 80 90 100 </pre> <p> <strong>Example 3:</strong> </p> <p>Let's take a program that prints the multiplication table of a given number N using a <strong> <em>do...while Loop</em> :</strong> </p> <pre> #include int main() { int N; printf('Enter a number to generate its multiplication table: '); scanf('%d', &N); inti = 1; do { printf('%d x %d = %d
', N, i, N * i); i++; } while (i<= 10); return 0; } < pre> <p> <strong>Output:</strong> </p> <p>Let us say you enter the number 7 as input:</p> <pre> Please enter a number to generate its multiplication table: 7 7 x 1 = 7 7 x 2 = 14 7 x 3 = 21 7 x 4 = 28 7 x 5 = 35 7 x 6 = 42 7 x 7 = 49 7 x 8 = 56 7 x 9 = 63 7 x 10 = 70 </pre> <p>The program calculates and prints the multiplication table for <strong> <em>7</em> </strong> from 1 to 10.</p> <h3>Infinite do while loop</h3> <p>An <strong> <em>infinite loop</em> </strong> is a loop that runs indefinitely as its condition is always <strong> <em>true</em> </strong> or it lacks a terminating condition. Here is an example of an <strong> <em>infinite do...while loop</em> </strong> in C:</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { inti = 1; do { printf('Iteration %d
', i); i++; } while (1); // Condition is always true return 0; } </pre> <p>In this <strong> <em>example</em> </strong> , the <strong> <em>loop</em> </strong> will keep running <strong> <em>indefinitely</em> </strong> because <strong> <em>condition 1</em> </strong> is always <strong> <em>true</em> </strong> .</p> <p> <strong>Output:</strong> </p> <p>When you run the program, you will see that it continues printing <strong> <em>'Iteration x',</em> </strong> where x is the <strong> <em>iteration number</em> </strong> without stopping:</p> <pre> Iteration 1 Iteration 2 Iteration 3 Iteration 4 Iteration 5 ... (and so on) </pre> <p>To interrupt an infinite loop like this, you generally use a <strong> <em>break statement</em> </strong> within the <strong> <em>loop</em> </strong> or some external condition you can control, such as <strong> <em>hitting</em> </strong> a specific key combination. In most desktop settings, the keyboard shortcut <strong> <em>Ctrl+C</em> </strong> can escape the Loop.</p> <h3>Nested do while loop in C</h3> <p>In C, we take an example of a <strong> <em>nested do...while loop</em> </strong> . In this example, we will write a program that uses <strong> <em>nested do...while loops</em> </strong> to create a numerical pattern.</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { int rows, i = 1; printf('Enter the number of rows: '); scanf('%d', &rows); do { int j = 1; do { printf('%d ', j); j++; } while (j <= i); printf('
'); i++; } while (i<="rows);" return 0; < pre> <p>In this program, we use <strong> <em>nested do...while loops</em> </strong> to generate a pattern of numbers. The <strong> <em>outer loop</em> </strong> controls the number of rows, and the <strong> <em>inner loop</em> </strong> generates the numbers for each row.</p> <p> <strong>Output:</strong> </p> <p>Let us say you input five as the number of rows:</p> <pre> Enter the number of rows: 5 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the program generates a pattern of numbers in a <strong> <em>triangular shape</em> </strong> . The <strong> <em>outer loop</em> </strong> iterates over the rows, and the <strong> <em>inner loop</em> </strong> iterates within each row, printing the numbers from 1 up to the current row number.</p> <h2>Difference between while and do while Loop</h2> <p>Here is a tabular comparison between the while loop and the do-while Loop in C:</p> <table class="table"> <tr> <th>Aspect</th> <th>while loop</th> <th>do-while loop</th> </tr> <tr> <td> <strong>Syntax</strong> </td> <td>while (condition) { ... }</td> <td>do { ... } while (condition);</td> </tr> <tr> <td> <strong>Loop Body Execution</strong> </td> <td>Condition is checked before execution.</td> <td>The body is executed before the condition.</td> </tr> <tr> <td> <strong>First Execution</strong> </td> <td>The condition must be true initially.</td> <td>The body is executed at least once.</td> </tr> <tr> <td> <strong>Loop Execution</strong> </td> <td>May execute zero or more times.</td> <td>Will execute at least once.</td> </tr> <tr> <td> <strong>Example</strong> </td> <td>while (i<5) { printf('%d
', i); i++; }< td> <td>do { printf('%d
', i); i++; } while (i<5);< td> </5);<></td></5)></td></tr> <tr> <td> <strong>Common Use Cases</strong> </td> <td>When the loop may not run at all.</td> <td>When you want the loop to run at least once.</td> </tr> </table> <p> <strong>While Loop:</strong> The loop body is executed before the condition is checked. If the condition is initially <strong> <em>false</em> </strong> , the loop may not execute.</p> <p> <strong>Do-while Loop:</strong> The <strong> <em>loop body</em> </strong> is executed at least once before the condition is <strong> <em>checked</em> </strong> . This guarantees that the loop completes at least one iteration.</p> <p>When you want the <strong> <em>loop</em> </strong> to run based on a condition that may be <strong> <em>false</em> </strong> at first, use the <strong> <em>while loop</em> </strong> , and when you want the loop to run at least once regardless of the starting state, use the <strong> <em>do-while loop.</em> </strong> </p> <h2>Features of do while loop</h2> <p>The do-while loop in C has several fundamental characteristics that make it an effective programming technique in certain situations. The following are the significant characteristics of the do-while loop:</p> <ul> <tr><td>Guaranteed Execution:</td> Unlike other <strong> <em>loop structures</em> </strong> , the <strong> <em>do-while oop</em> </strong> ensures that the loop body is executed at least once. Because the condition is assessed after the loop body, the code within the loop is performed before the condition is verified. </tr><tr><td>Loop after testing:</td> The <strong> <em>do-while loop</em> </strong> is a post-tested loop which implies that the loop condition is assessed after the loop body has been executed. If the condition is true, the loop body is run once again. This behavior allows you to verify the condition for repetition before ensuring that a given activity is completed. </tr><tr><td>Conditionally Controlled:</td> The loop continues to execute as long as the condition specified after the while keyword remains <strong> <em>true</em> </strong> . When the condition evaluates to <strong> <em>false</em> </strong> , the loop is terminated, and control shifts to the sentence after the loop. </tr><tr><td>Flexibility:</td> The <strong> <em>do-while loop</em> </strong> may be utilized in several contexts. It is typically used in cases where a piece of code must be executed at least once, such as <strong> <em>menu-driven programs, input validation,</em> </strong> or <strong> <em>repetitive computations</em> </strong> . </tr><tr><td>Nesting Capability:</td> Similar to other <strong> <em>loop constructs</em> </strong> , the <strong> <em>do-while loop</em> </strong> can be <strong> <em>nested</em> </strong> inside other <strong> <em>loops</em> </strong> or <strong> <em>control structures</em> </strong> to create more complex control flow patterns. It allows for the creation of <strong> <em>nested loops</em> </strong> and the implementation of intricate repetitive tasks. </tr><tr><td>Break and Continue:</td> The break statement can be used within a <strong> <em>do-while loop</em> </strong> to terminate the loop execution and exit the loop prematurely. The <strong> <em>continue statement</em> </strong> can skip the remaining code in the current iteration and jump to the next iteration of the loop. </tr><tr><td>Local Scope:</td> Variables declared inside the <strong> <em>do-while loop</em> </strong> body have local scope and are accessible only within the <strong> <em>loop block.</em> </strong> They cannot be accessed outside the loop or by other loops or control structures. </tr><tr><td>Infinite Loop Control:</td> It is crucial to ensure that the loop's condition is eventually modified within the <strong> <em>loop body</em> </strong> . This modification is necessary to prevent infinite loops where the condition continually evaluates to true. Modifying the condition ensures that the loop terminates at some point. </tr></ul> <hr></=></pre></=></pre></=10);></pre></=> Obrazloženje:
U ovom primjeru, blok koda unutar do petlje će se izvršiti barem jednom, ispisujući brojeve iz 1 do 5 . Nakon svakog ponavljanja, cijenim se povećava, a stanje i<= 5< em> je provjereno. Ako je uvjet još uvijek istinit, petlja se nastavlja; inače se prekida.
Primjer 2:
Program za ispis tablice za zadani broj pomoću petlje do while
#include intmain(){ inti=1,number=0; printf('Enter a number: '); scanf('%d',&number); do{ printf('%d
',(number*i)); i++; }while(i<=10); return 0; } < pre> <p> <strong>Output:</strong> </p> <pre> Enter a number: 5 5 10 15 20 25 30 35 40 45 50 Enter a number: 10 10 20 30 40 50 60 70 80 90 100 </pre> <p> <strong>Example 3:</strong> </p> <p>Let's take a program that prints the multiplication table of a given number N using a <strong> <em>do...while Loop</em> :</strong> </p> <pre> #include int main() { int N; printf('Enter a number to generate its multiplication table: '); scanf('%d', &N); inti = 1; do { printf('%d x %d = %d
', N, i, N * i); i++; } while (i<= 10); return 0; } < pre> <p> <strong>Output:</strong> </p> <p>Let us say you enter the number 7 as input:</p> <pre> Please enter a number to generate its multiplication table: 7 7 x 1 = 7 7 x 2 = 14 7 x 3 = 21 7 x 4 = 28 7 x 5 = 35 7 x 6 = 42 7 x 7 = 49 7 x 8 = 56 7 x 9 = 63 7 x 10 = 70 </pre> <p>The program calculates and prints the multiplication table for <strong> <em>7</em> </strong> from 1 to 10.</p> <h3>Infinite do while loop</h3> <p>An <strong> <em>infinite loop</em> </strong> is a loop that runs indefinitely as its condition is always <strong> <em>true</em> </strong> or it lacks a terminating condition. Here is an example of an <strong> <em>infinite do...while loop</em> </strong> in C:</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { inti = 1; do { printf('Iteration %d
', i); i++; } while (1); // Condition is always true return 0; } </pre> <p>In this <strong> <em>example</em> </strong> , the <strong> <em>loop</em> </strong> will keep running <strong> <em>indefinitely</em> </strong> because <strong> <em>condition 1</em> </strong> is always <strong> <em>true</em> </strong> .</p> <p> <strong>Output:</strong> </p> <p>When you run the program, you will see that it continues printing <strong> <em>'Iteration x',</em> </strong> where x is the <strong> <em>iteration number</em> </strong> without stopping:</p> <pre> Iteration 1 Iteration 2 Iteration 3 Iteration 4 Iteration 5 ... (and so on) </pre> <p>To interrupt an infinite loop like this, you generally use a <strong> <em>break statement</em> </strong> within the <strong> <em>loop</em> </strong> or some external condition you can control, such as <strong> <em>hitting</em> </strong> a specific key combination. In most desktop settings, the keyboard shortcut <strong> <em>Ctrl+C</em> </strong> can escape the Loop.</p> <h3>Nested do while loop in C</h3> <p>In C, we take an example of a <strong> <em>nested do...while loop</em> </strong> . In this example, we will write a program that uses <strong> <em>nested do...while loops</em> </strong> to create a numerical pattern.</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { int rows, i = 1; printf('Enter the number of rows: '); scanf('%d', &rows); do { int j = 1; do { printf('%d ', j); j++; } while (j <= i); printf(\'
\'); i++; } while (i<="rows);" return 0; < pre> <p>In this program, we use <strong> <em>nested do...while loops</em> </strong> to generate a pattern of numbers. The <strong> <em>outer loop</em> </strong> controls the number of rows, and the <strong> <em>inner loop</em> </strong> generates the numbers for each row.</p> <p> <strong>Output:</strong> </p> <p>Let us say you input five as the number of rows:</p> <pre> Enter the number of rows: 5 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the program generates a pattern of numbers in a <strong> <em>triangular shape</em> </strong> . The <strong> <em>outer loop</em> </strong> iterates over the rows, and the <strong> <em>inner loop</em> </strong> iterates within each row, printing the numbers from 1 up to the current row number.</p> <h2>Difference between while and do while Loop</h2> <p>Here is a tabular comparison between the while loop and the do-while Loop in C:</p> <table class="table"> <tr> <th>Aspect</th> <th>while loop</th> <th>do-while loop</th> </tr> <tr> <td> <strong>Syntax</strong> </td> <td>while (condition) { ... }</td> <td>do { ... } while (condition);</td> </tr> <tr> <td> <strong>Loop Body Execution</strong> </td> <td>Condition is checked before execution.</td> <td>The body is executed before the condition.</td> </tr> <tr> <td> <strong>First Execution</strong> </td> <td>The condition must be true initially.</td> <td>The body is executed at least once.</td> </tr> <tr> <td> <strong>Loop Execution</strong> </td> <td>May execute zero or more times.</td> <td>Will execute at least once.</td> </tr> <tr> <td> <strong>Example</strong> </td> <td>while (i<5) { printf(\'%d
\', i); i++; }< td> <td>do { printf('%d
', i); i++; } while (i<5);< td> </5);<></td></5)></td></tr> <tr> <td> <strong>Common Use Cases</strong> </td> <td>When the loop may not run at all.</td> <td>When you want the loop to run at least once.</td> </tr> </table> <p> <strong>While Loop:</strong> The loop body is executed before the condition is checked. If the condition is initially <strong> <em>false</em> </strong> , the loop may not execute.</p> <p> <strong>Do-while Loop:</strong> The <strong> <em>loop body</em> </strong> is executed at least once before the condition is <strong> <em>checked</em> </strong> . This guarantees that the loop completes at least one iteration.</p> <p>When you want the <strong> <em>loop</em> </strong> to run based on a condition that may be <strong> <em>false</em> </strong> at first, use the <strong> <em>while loop</em> </strong> , and when you want the loop to run at least once regardless of the starting state, use the <strong> <em>do-while loop.</em> </strong> </p> <h2>Features of do while loop</h2> <p>The do-while loop in C has several fundamental characteristics that make it an effective programming technique in certain situations. The following are the significant characteristics of the do-while loop:</p> <ul> <tr><td>Guaranteed Execution:</td> Unlike other <strong> <em>loop structures</em> </strong> , the <strong> <em>do-while oop</em> </strong> ensures that the loop body is executed at least once. Because the condition is assessed after the loop body, the code within the loop is performed before the condition is verified. </tr><tr><td>Loop after testing:</td> The <strong> <em>do-while loop</em> </strong> is a post-tested loop which implies that the loop condition is assessed after the loop body has been executed. If the condition is true, the loop body is run once again. This behavior allows you to verify the condition for repetition before ensuring that a given activity is completed. </tr><tr><td>Conditionally Controlled:</td> The loop continues to execute as long as the condition specified after the while keyword remains <strong> <em>true</em> </strong> . When the condition evaluates to <strong> <em>false</em> </strong> , the loop is terminated, and control shifts to the sentence after the loop. </tr><tr><td>Flexibility:</td> The <strong> <em>do-while loop</em> </strong> may be utilized in several contexts. It is typically used in cases where a piece of code must be executed at least once, such as <strong> <em>menu-driven programs, input validation,</em> </strong> or <strong> <em>repetitive computations</em> </strong> . </tr><tr><td>Nesting Capability:</td> Similar to other <strong> <em>loop constructs</em> </strong> , the <strong> <em>do-while loop</em> </strong> can be <strong> <em>nested</em> </strong> inside other <strong> <em>loops</em> </strong> or <strong> <em>control structures</em> </strong> to create more complex control flow patterns. It allows for the creation of <strong> <em>nested loops</em> </strong> and the implementation of intricate repetitive tasks. </tr><tr><td>Break and Continue:</td> The break statement can be used within a <strong> <em>do-while loop</em> </strong> to terminate the loop execution and exit the loop prematurely. The <strong> <em>continue statement</em> </strong> can skip the remaining code in the current iteration and jump to the next iteration of the loop. </tr><tr><td>Local Scope:</td> Variables declared inside the <strong> <em>do-while loop</em> </strong> body have local scope and are accessible only within the <strong> <em>loop block.</em> </strong> They cannot be accessed outside the loop or by other loops or control structures. </tr><tr><td>Infinite Loop Control:</td> It is crucial to ensure that the loop's condition is eventually modified within the <strong> <em>loop body</em> </strong> . This modification is necessary to prevent infinite loops where the condition continually evaluates to true. Modifying the condition ensures that the loop terminates at some point. </tr></ul> <hr></=></pre></=></pre></=10);> Primjer 3:
Uzmimo program koji ispisuje tablicu množenja zadanog broja N koristeći a do...while Petlja :
#include int main() { int N; printf('Enter a number to generate its multiplication table: '); scanf('%d', &N); inti = 1; do { printf('%d x %d = %d
', N, i, N * i); i++; } while (i<= 10); return 0; } < pre> <p> <strong>Output:</strong> </p> <p>Let us say you enter the number 7 as input:</p> <pre> Please enter a number to generate its multiplication table: 7 7 x 1 = 7 7 x 2 = 14 7 x 3 = 21 7 x 4 = 28 7 x 5 = 35 7 x 6 = 42 7 x 7 = 49 7 x 8 = 56 7 x 9 = 63 7 x 10 = 70 </pre> <p>The program calculates and prints the multiplication table for <strong> <em>7</em> </strong> from 1 to 10.</p> <h3>Infinite do while loop</h3> <p>An <strong> <em>infinite loop</em> </strong> is a loop that runs indefinitely as its condition is always <strong> <em>true</em> </strong> or it lacks a terminating condition. Here is an example of an <strong> <em>infinite do...while loop</em> </strong> in C:</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { inti = 1; do { printf('Iteration %d
', i); i++; } while (1); // Condition is always true return 0; } </pre> <p>In this <strong> <em>example</em> </strong> , the <strong> <em>loop</em> </strong> will keep running <strong> <em>indefinitely</em> </strong> because <strong> <em>condition 1</em> </strong> is always <strong> <em>true</em> </strong> .</p> <p> <strong>Output:</strong> </p> <p>When you run the program, you will see that it continues printing <strong> <em>'Iteration x',</em> </strong> where x is the <strong> <em>iteration number</em> </strong> without stopping:</p> <pre> Iteration 1 Iteration 2 Iteration 3 Iteration 4 Iteration 5 ... (and so on) </pre> <p>To interrupt an infinite loop like this, you generally use a <strong> <em>break statement</em> </strong> within the <strong> <em>loop</em> </strong> or some external condition you can control, such as <strong> <em>hitting</em> </strong> a specific key combination. In most desktop settings, the keyboard shortcut <strong> <em>Ctrl+C</em> </strong> can escape the Loop.</p> <h3>Nested do while loop in C</h3> <p>In C, we take an example of a <strong> <em>nested do...while loop</em> </strong> . In this example, we will write a program that uses <strong> <em>nested do...while loops</em> </strong> to create a numerical pattern.</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { int rows, i = 1; printf('Enter the number of rows: '); scanf('%d', &rows); do { int j = 1; do { printf('%d ', j); j++; } while (j <= i); printf(\'
\'); i++; } while (i<="rows);" return 0; < pre> <p>In this program, we use <strong> <em>nested do...while loops</em> </strong> to generate a pattern of numbers. The <strong> <em>outer loop</em> </strong> controls the number of rows, and the <strong> <em>inner loop</em> </strong> generates the numbers for each row.</p> <p> <strong>Output:</strong> </p> <p>Let us say you input five as the number of rows:</p> <pre> Enter the number of rows: 5 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the program generates a pattern of numbers in a <strong> <em>triangular shape</em> </strong> . The <strong> <em>outer loop</em> </strong> iterates over the rows, and the <strong> <em>inner loop</em> </strong> iterates within each row, printing the numbers from 1 up to the current row number.</p> <h2>Difference between while and do while Loop</h2> <p>Here is a tabular comparison between the while loop and the do-while Loop in C:</p> <table class="table"> <tr> <th>Aspect</th> <th>while loop</th> <th>do-while loop</th> </tr> <tr> <td> <strong>Syntax</strong> </td> <td>while (condition) { ... }</td> <td>do { ... } while (condition);</td> </tr> <tr> <td> <strong>Loop Body Execution</strong> </td> <td>Condition is checked before execution.</td> <td>The body is executed before the condition.</td> </tr> <tr> <td> <strong>First Execution</strong> </td> <td>The condition must be true initially.</td> <td>The body is executed at least once.</td> </tr> <tr> <td> <strong>Loop Execution</strong> </td> <td>May execute zero or more times.</td> <td>Will execute at least once.</td> </tr> <tr> <td> <strong>Example</strong> </td> <td>while (i<5) { printf(\'%d
\', i); i++; }< td> <td>do { printf('%d
', i); i++; } while (i<5);< td> </5);<></td></5)></td></tr> <tr> <td> <strong>Common Use Cases</strong> </td> <td>When the loop may not run at all.</td> <td>When you want the loop to run at least once.</td> </tr> </table> <p> <strong>While Loop:</strong> The loop body is executed before the condition is checked. If the condition is initially <strong> <em>false</em> </strong> , the loop may not execute.</p> <p> <strong>Do-while Loop:</strong> The <strong> <em>loop body</em> </strong> is executed at least once before the condition is <strong> <em>checked</em> </strong> . This guarantees that the loop completes at least one iteration.</p> <p>When you want the <strong> <em>loop</em> </strong> to run based on a condition that may be <strong> <em>false</em> </strong> at first, use the <strong> <em>while loop</em> </strong> , and when you want the loop to run at least once regardless of the starting state, use the <strong> <em>do-while loop.</em> </strong> </p> <h2>Features of do while loop</h2> <p>The do-while loop in C has several fundamental characteristics that make it an effective programming technique in certain situations. The following are the significant characteristics of the do-while loop:</p> <ul> <tr><td>Guaranteed Execution:</td> Unlike other <strong> <em>loop structures</em> </strong> , the <strong> <em>do-while oop</em> </strong> ensures that the loop body is executed at least once. Because the condition is assessed after the loop body, the code within the loop is performed before the condition is verified. </tr><tr><td>Loop after testing:</td> The <strong> <em>do-while loop</em> </strong> is a post-tested loop which implies that the loop condition is assessed after the loop body has been executed. If the condition is true, the loop body is run once again. This behavior allows you to verify the condition for repetition before ensuring that a given activity is completed. </tr><tr><td>Conditionally Controlled:</td> The loop continues to execute as long as the condition specified after the while keyword remains <strong> <em>true</em> </strong> . When the condition evaluates to <strong> <em>false</em> </strong> , the loop is terminated, and control shifts to the sentence after the loop. </tr><tr><td>Flexibility:</td> The <strong> <em>do-while loop</em> </strong> may be utilized in several contexts. It is typically used in cases where a piece of code must be executed at least once, such as <strong> <em>menu-driven programs, input validation,</em> </strong> or <strong> <em>repetitive computations</em> </strong> . </tr><tr><td>Nesting Capability:</td> Similar to other <strong> <em>loop constructs</em> </strong> , the <strong> <em>do-while loop</em> </strong> can be <strong> <em>nested</em> </strong> inside other <strong> <em>loops</em> </strong> or <strong> <em>control structures</em> </strong> to create more complex control flow patterns. It allows for the creation of <strong> <em>nested loops</em> </strong> and the implementation of intricate repetitive tasks. </tr><tr><td>Break and Continue:</td> The break statement can be used within a <strong> <em>do-while loop</em> </strong> to terminate the loop execution and exit the loop prematurely. The <strong> <em>continue statement</em> </strong> can skip the remaining code in the current iteration and jump to the next iteration of the loop. </tr><tr><td>Local Scope:</td> Variables declared inside the <strong> <em>do-while loop</em> </strong> body have local scope and are accessible only within the <strong> <em>loop block.</em> </strong> They cannot be accessed outside the loop or by other loops or control structures. </tr><tr><td>Infinite Loop Control:</td> It is crucial to ensure that the loop's condition is eventually modified within the <strong> <em>loop body</em> </strong> . This modification is necessary to prevent infinite loops where the condition continually evaluates to true. Modifying the condition ensures that the loop terminates at some point. </tr></ul> <hr></=></pre></=> Program izračunava i ispisuje tablicu množenja za 7 od 1 do 10.
Beskonačna do while petlja
An beskonačna petlja je petlja koja radi beskonačno jer je njezin uvjet uvijek pravi ili mu nedostaje završni uvjet. Evo primjera beskonačna do...while petlja u C:
Primjer:
#include int main() { inti = 1; do { printf('Iteration %d
', i); i++; } while (1); // Condition is always true return 0; } U ovom primjer , the petlja nastavit će trčati neodređeno jer stanje 1 je uvijek pravi .
Izlaz:
Kada pokrenete program, vidjet ćete da nastavlja s ispisom 'Iteracija x', gdje je x broj ponavljanja bez stajanja:
Iteration 1 Iteration 2 Iteration 3 Iteration 4 Iteration 5 ... (and so on)
Za prekid beskonačne petlje kao što je ova, općenito koristite a break izjava unutar petlja ili neki vanjski uvjet koji možete kontrolirati, kao što je udaranje određena kombinacija tipki. U većini postavki radne površine, tipkovnički prečac Ctrl+C može pobjeći iz Petlje.
Ugniježđena do while petlja u C-u
U C-u uzimamo primjer a ugniježđena do...while petlja . U ovom primjeru ćemo napisati program koji koristi ugniježđene do...while petlje za stvaranje numeričkog uzorka.
Primjer:
#include int main() { int rows, i = 1; printf('Enter the number of rows: '); scanf('%d', &rows); do { int j = 1; do { printf('%d ', j); j++; } while (j <= i); printf(\'
\'); i++; } while (i<="rows);" return 0; < pre> <p>In this program, we use <strong> <em>nested do...while loops</em> </strong> to generate a pattern of numbers. The <strong> <em>outer loop</em> </strong> controls the number of rows, and the <strong> <em>inner loop</em> </strong> generates the numbers for each row.</p> <p> <strong>Output:</strong> </p> <p>Let us say you input five as the number of rows:</p> <pre> Enter the number of rows: 5 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the program generates a pattern of numbers in a <strong> <em>triangular shape</em> </strong> . The <strong> <em>outer loop</em> </strong> iterates over the rows, and the <strong> <em>inner loop</em> </strong> iterates within each row, printing the numbers from 1 up to the current row number.</p> <h2>Difference between while and do while Loop</h2> <p>Here is a tabular comparison between the while loop and the do-while Loop in C:</p> <table class="table"> <tr> <th>Aspect</th> <th>while loop</th> <th>do-while loop</th> </tr> <tr> <td> <strong>Syntax</strong> </td> <td>while (condition) { ... }</td> <td>do { ... } while (condition);</td> </tr> <tr> <td> <strong>Loop Body Execution</strong> </td> <td>Condition is checked before execution.</td> <td>The body is executed before the condition.</td> </tr> <tr> <td> <strong>First Execution</strong> </td> <td>The condition must be true initially.</td> <td>The body is executed at least once.</td> </tr> <tr> <td> <strong>Loop Execution</strong> </td> <td>May execute zero or more times.</td> <td>Will execute at least once.</td> </tr> <tr> <td> <strong>Example</strong> </td> <td>while (i<5) { printf(\'%d
\', i); i++; }< td> <td>do { printf('%d
', i); i++; } while (i<5);< td> </5);<></td></5)></td></tr> <tr> <td> <strong>Common Use Cases</strong> </td> <td>When the loop may not run at all.</td> <td>When you want the loop to run at least once.</td> </tr> </table> <p> <strong>While Loop:</strong> The loop body is executed before the condition is checked. If the condition is initially <strong> <em>false</em> </strong> , the loop may not execute.</p> <p> <strong>Do-while Loop:</strong> The <strong> <em>loop body</em> </strong> is executed at least once before the condition is <strong> <em>checked</em> </strong> . This guarantees that the loop completes at least one iteration.</p> <p>When you want the <strong> <em>loop</em> </strong> to run based on a condition that may be <strong> <em>false</em> </strong> at first, use the <strong> <em>while loop</em> </strong> , and when you want the loop to run at least once regardless of the starting state, use the <strong> <em>do-while loop.</em> </strong> </p> <h2>Features of do while loop</h2> <p>The do-while loop in C has several fundamental characteristics that make it an effective programming technique in certain situations. The following are the significant characteristics of the do-while loop:</p> <ul> <tr><td>Guaranteed Execution:</td> Unlike other <strong> <em>loop structures</em> </strong> , the <strong> <em>do-while oop</em> </strong> ensures that the loop body is executed at least once. Because the condition is assessed after the loop body, the code within the loop is performed before the condition is verified. </tr><tr><td>Loop after testing:</td> The <strong> <em>do-while loop</em> </strong> is a post-tested loop which implies that the loop condition is assessed after the loop body has been executed. If the condition is true, the loop body is run once again. This behavior allows you to verify the condition for repetition before ensuring that a given activity is completed. </tr><tr><td>Conditionally Controlled:</td> The loop continues to execute as long as the condition specified after the while keyword remains <strong> <em>true</em> </strong> . When the condition evaluates to <strong> <em>false</em> </strong> , the loop is terminated, and control shifts to the sentence after the loop. </tr><tr><td>Flexibility:</td> The <strong> <em>do-while loop</em> </strong> may be utilized in several contexts. It is typically used in cases where a piece of code must be executed at least once, such as <strong> <em>menu-driven programs, input validation,</em> </strong> or <strong> <em>repetitive computations</em> </strong> . </tr><tr><td>Nesting Capability:</td> Similar to other <strong> <em>loop constructs</em> </strong> , the <strong> <em>do-while loop</em> </strong> can be <strong> <em>nested</em> </strong> inside other <strong> <em>loops</em> </strong> or <strong> <em>control structures</em> </strong> to create more complex control flow patterns. It allows for the creation of <strong> <em>nested loops</em> </strong> and the implementation of intricate repetitive tasks. </tr><tr><td>Break and Continue:</td> The break statement can be used within a <strong> <em>do-while loop</em> </strong> to terminate the loop execution and exit the loop prematurely. The <strong> <em>continue statement</em> </strong> can skip the remaining code in the current iteration and jump to the next iteration of the loop. </tr><tr><td>Local Scope:</td> Variables declared inside the <strong> <em>do-while loop</em> </strong> body have local scope and are accessible only within the <strong> <em>loop block.</em> </strong> They cannot be accessed outside the loop or by other loops or control structures. </tr><tr><td>Infinite Loop Control:</td> It is crucial to ensure that the loop's condition is eventually modified within the <strong> <em>loop body</em> </strong> . This modification is necessary to prevent infinite loops where the condition continually evaluates to true. Modifying the condition ensures that the loop terminates at some point. </tr></ul> <hr></=> Obrazloženje:
U ovom primjeru program generira uzorak brojeva u a trokutasti oblik . The vanjska petlja ponavlja redove, i unutarnja petlja ponavlja unutar svakog retka, ispisuje brojeve od 1 do trenutnog broja retka.
Razlika između while i do while petlje
Ovdje je tablična usporedba petlje while i do-while petlje u C-u:
| Aspekt | while petlja | do-while petlja |
|---|---|---|
| Sintaksa | dok (uvjet) { ... } | do { ... } dok (uvjet); |
| Izvođenje tijela petlje | Stanje se provjerava prije izvršenja. | Tijelo se izvršava prije uvjeta. |
| Prvo izvršenje | Uvjet u početku mora biti istinit. | Tijelo se pogubljuje najmanje jednom. |
| Izvršenje petlje | Može se izvršiti nula ili više puta. | Izvršit će se barem jednom. |
| Primjer | dok ja<5) { printf(\'%d \', i); i++; }< td> | do { printf('%d ', i); i++; } dok ja<5);< td> |
| Uobičajeni slučajevi upotrebe | Kada se petlja možda uopće neće pokrenuti. | Kada želite da se petlja pokrene barem jednom. |
Dok petlja: Tijelo petlje se izvršava prije provjere uvjeta. Ako je stanje inicijalno lažno , petlja se možda neće izvršiti.
Do-while petlja: The tijelo petlje se izvršava najmanje jednom prije uvjeta provjereno . Ovo jamči da petlja završi najmanje jednu iteraciju.
otočić java
Kada želite petlja pokrenuti na temelju stanja koje može biti lažno u početku koristite while petlja , a kada želite da se petlja pokrene barem jednom bez obzira na početno stanje, koristite do-while petlja.
Značajke do while petlje
Do-while petlja u C-u ima nekoliko temeljnih karakteristika koje je čine učinkovitom tehnikom programiranja u određenim situacijama. Sljedeće su značajne karakteristike do-while petlje: