abs() function in C

abs() function is a built-in function present in the stdlib.h header file. It returns an integer value. abs() function converts a negative value into a positive value. For example, if we give -10 as input, it returns 10. If we give a positive number, it returns the same number. To use abs() function in the program, we must include stdlib.h header file.

Syntax :

a= abs(number);

Format of abs() function: int abs( int n );

It takes an integer value as the parameter and returns the positive number.

Advantages of abs() function:

1. It converts the negative value into a positive value.
2. Lines of code get reduced.
3. Easy to learn.

// sample program to find the absolute value of given number using abs() function
#include <stdio.h>  
#include <stdlib.h> // including the header file 
int main()  
{  
    int number, abslute_value; // declare the local variable  
    printf (" Enter the number to convert it into absolute  value: ");
    scanf ("%d", &number);  // reading the input
    abslute_value= abs (number);  // function call
    // printing the absalute value
    printf ("\n The absolute value of %d is %d. ", number, abslute_value); 
    return 0;
}  

Output: Test case 1

Enter the number to convert it into absolute  value: -100
The absolute value of -100 is 100.

In this test case, we gave a negative number as input, and it returned a positive number.

Output: Test case 2

Enter the number to convert it into absolute  value: 100
The absolute value of 100 is 100.

In this test case we gave positive number as input and it returned positive number.

// sample program to find the absolute value of given number without using abs() function
#include <stdio.h>  
#include <stdlib.h> // including the header file 
int main()  
{  
    int number, abslute_value; // declare the local variable  
    printf (" Enter the number to convert it into absolute  value: ");
    scanf ("%d", &number);  // reading the input
    abslute_value= -1*number;  // function call
    // printing the absalute value
    printf ("\n The absolute value of %d without using abs() function is %d. ", number, abslute_value); 
    return 0;
}  

Output:

Enter the number to convert it into absolute  value: -10
The absolute value of -10 without using abs() function is 10.

Example to find the square root of the given number.

// program to find square root of the given number
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main() {
    int number, absalute_value, square_root; // variable  declaration
    printf("Enter the number: ");
    scanf("%d", &number); // reading the number
    // calculating the absalute value
    absalute_value = abs( number ); // function call
    printf(" \nThe absalute value of the given number is: %d",absalute_value); // printing the absalute value
    // calculating the square root value
    square_root = sqrt(absalute_value); // function call
    printf(" \nThe square root value of the given number: %d",square_root); // printing square root value
    return 0;

Output:

Enter the number: -16
The absolute value of the given number is: 16 
The square root value of the given number: 4

Example program of abs() function on arrays:

// program to print the absalute values of the given array
#define max 100
#include <stdio.h>
#include<stdlib.h>
int main()
{
    int n, a[max], i, b[max];
    printf(" Enter the size of the array: ");
    scanf(" %d", &n); // reading the array size
    // Reading the array elements
    printf(" \nEnter the array elements: ");
    for( i=0; i<n; i++)
    {
        scanf(" %d", &a[i]); 
    }
    // finding the absalute value
      for( i=0; i<n; i++)
    {
        b[i] = abs ( a[i] ); // function call
    }
    // printing the absalute values
      for( i=0; i<n; i++)
    {
        printf(" \nThe absolute value of %d is  %d",a[i],b[i]);
    }
    return 0;
}

Output:

Enter the size of the array: 10
 Enter the array elements: 1 2 3 4 5 -6 -7 -8 -9 -10
 The absolute value of 1 is  1 
The absolute value of 2 is  2 
The absolute value of 3 is  3 
The absolute value of 4 is  4 
The absolute value of 5 is  5 
The absolute value of -6 is  6 
The absolute value of -7 is  7 
The absolute value of -8 is  8 
The absolute value of -9 is  9 
The absolute value of -10 is  10

Example program to find absolute values of the array without using abs() function:

// program to print the absalute values of the given array with out using abs() function
#define max 100
#include <stdio.h>
#include<stdlib.h>
int main()
{
    int n, a[max], i, b[max];
    printf(" Enter the size of the array: ");
    scanf(" %d", &n); // reading the array size
    // Reading the array elements
    printf(" \nEnter the array elements: ");
    for( i=0; i<n; i++)
    {
        scanf(" %d", &a[i]); 
    }
    // finding the absalute value
      for( i=0; i<n; i++)
    {
        if(a[i]<0)
        {
            b[i] = a[i] - 2*a[i];
        }
        else
        {
            b[i] = a[i];
        }
    }
    // printing the absalute values
      for( i=0; i<n; i++)
    {
        printf(" \nThe absolute value of %d is  %d",a[i],b[i]);
    }
    return 0;
}

Output:

Enter the size of the array: 10
Enter the array elements: 10 20 30 40 50 -60 -70 -80 -90 -100
The absolute value of 10 is  10 
The absolute value of 20 is  20 
The absolute value of 30 is  30 
The absolute value of 40 is  40 
The absolute value of 50 is  50 
The absolute value of -60 is  60 
The absolute value of -70 is  70 
The absolute value of -80 is  80 
The absolute value of -90 is  90 
The absolute value of -100 is  100

Conclusion:

In this article we learned about abs() function in C. The definition of abs() function, advantages of abs() function, examples on abs() function.