abs() in C: Absolute Value

abs() returns the absolute value of an int. It is declared in <stdlib.h>. The result is non-negative for representable inputs.

Syntax Top ↑

int abs(int value);

Basic Example Top ↑

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    int value = -25;

    printf("%d\n", abs(value));
    return 0;
}

Output

25

Absolute Difference Top ↑

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    int a = 42;
    int b = 57;

    printf("Difference: %d\n", abs(a - b));
    return 0;
}

For floating-point values use fabs() from <math.h>, not abs().

Preserved Type-Specific abs() Examples Top ↑

Floating-Point Absolute Value with fabs()

#include <math.h>
#include <stdio.h>

int main(void) {
    double first = 12.35;
    double second = -35.45;

    printf("%.2f\n", fabs(first));
    printf("%.2f\n", fabs(second));

    return 0;
}

Long Integer Absolute Value with labs()

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    long first = 123456L;
    long second = -3456789L;

    printf("%ld\n", labs(first));
    printf("%ld\n", labs(second));

    return 0;
}

abs() with User Input

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    int value;

    printf("Enter an integer: ");
    if (scanf("%d", &value) != 1) {
        printf("Invalid input.\n");
        return 1;
    }

    printf("Absolute value: %d\n", abs(value));
    return 0;
}

Subhendu Mohapatra

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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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