do...while Loop in C Programming

A do...while loop executes its body first and checks the condition afterward. Because the test happens at the end, the body always runs at least once.

do...while Syntax Top ↑

do {
    // statements
} while (condition);

The semicolon after the closing while (condition) is required.

Print 1 to 5 Top ↑

#include <stdio.h>

int main(void) {
    int i = 1;

    do {
        printf("%d\n", i);
        i++;
    } while (i <= 5);

    return 0;
}

Output

1
2
3
4
5

The Body Runs Once Even When the Condition Is False Top ↑

#include <stdio.h>

int main(void) {
    int i = 50;

    do {
        printf("Executed once; i = %d\n", i);
    } while (i >= 100);

    return 0;
}

Output

Executed once; i = 50

This is the key difference from a while loop, which checks its condition before entering the body.

Avoid Infinite do...while Loops Top ↑

int i = 1;

do {
    printf("%d\n", i);
    // Missing i++ means i stays 1.
} while (i <= 5);

break in a do...while Loop Top ↑

#include <stdio.h>

int main(void) {
    int i = 1;

    do {
        if (i == 4) {
            break;
        }

        printf("%d\n", i);
        i++;
    } while (i <= 5);

    return 0;
}

Output

1
2
3

continue in a do...while Loop Top ↑

#include <stdio.h>

int main(void) {
    int i = 0;

    do {
        i++;

        if (i == 3) {
            continue;
        }

        printf("%d\n", i);
    } while (i < 5);

    return 0;
}

Output

1
2
4
5

In a do...while loop, continue jumps to the condition check at the bottom.

Decrement by 10 Top ↑

#include <stdio.h>

int main(void) {
    int i = 50;

    do {
        printf("%d\n", i);
        i -= 10;
    } while (i >= 0);

    return 0;
}

Output

50
40
30
20
10
0

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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