llabs() Function

The llabs() function is declared in the header file <stdlib.h>.

The llabs() function returns the absolute value of a given integral value, ensuring that the result is always non-negative. This function is specifically designed to work with values of type long long int, providing a long long version of the standard abs() function.

Syntax of llabs()

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long long int llabs(long long int n);

Parameters

ParameterDescription
nAn integral value of type long long int whose absolute value is to be computed.

It is worth noting that this function computes the absolute value of the input, returning the non-negative value of n. This can be particularly useful when dealing with large integers that require a wider range than the standard int type.

Return Value

The function returns the absolute value of n as a long long int.

Examples for llabs()

Example 1: Basic Absolute Value Computation

This example demonstrates the basic usage of llabs() by computing the absolute value of a negative number.

Program

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

int main() {
    long long int num = -123456789012345LL;
    long long int absValue = llabs(num);

    printf("The absolute value of %lld is %lld.\n", num, absValue);
    return 0;
}

Explanation:

  1. A long long int variable num is initialized with a negative value.
  2. The llabs() function is called to compute the absolute value of num.
  3. The absolute value is stored in absValue and then printed.

Program Output:

The absolute value of -123456789012345 is 123456789012345.

Example 2: Handling Zero and Positive Numbers

This example checks how llabs() works with zero and a positive number, ensuring that the function correctly returns the input when it is non-negative.

Program

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

int main() {
    long long int values[] = {0, 98765432109876LL};
    int i;

    for (i = 0; i < 2; i++) {
        printf("The absolute value of %lld is %lld.\n", values[i], llabs(values[i]));
    }

    return 0;
}

Explanation:

  1. An array values is initialized with two long long int values: zero and a positive number.
  2. The program iterates through the array, using llabs() to compute and print the absolute value for each element.
  3. The function returns the same value when the input is non-negative.

Program Output:

The absolute value of 0 is 0.
The absolute value of 98765432109876 is 98765432109876.

Example 3: Using llabs() in a Function

This example demonstrates how to integrate llabs() within a custom function that processes an array of long long int values by converting each element to its absolute value.

Program

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

void printAbsoluteValues(long long int arr[], int size) {
    for (int i = 0; i < size; i++) {
        printf("Absolute value of %lld is %lld.\n", arr[i], llabs(arr[i]));
    }
}

int main() {
    long long int numbers[] = {-10LL, 20LL, -30LL, 40LL, -50LL};
    int n = sizeof(numbers) / sizeof(numbers[0]);

    printAbsoluteValues(numbers, n);
    return 0;
}

Explanation:

  1. A helper function printAbsoluteValues() is defined to iterate over an array of long long int values.
  2. The function calls llabs() for each element to compute its absolute value and prints the result.
  3. The main function initializes an array of both negative and positive numbers and calls the helper function.

Program Output:

Absolute value of -10 is 10.
Absolute value of 20 is 20.
Absolute value of -30 is 30.
Absolute value of 40 is 40.
Absolute value of -50 is 50.