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Program to find absolute value of a given number
  • Last Updated : 26 Mar, 2021

Given an integer N, the task is to find the absolute value of the given integer.
Examples: 
 

Input: N = -6 
Output: 6
Input: N = 12 
Output: 12 
 

 

Method 1 – Naive Approach: Since the absolute value of any number is always positive. For any positive number, the absolute value is the number itself and for any negative number, the absolute value is (-1) multiplied by the negative number. 
 

C++




// C++ program for Method 1
#include <bits/stdc++.h>
using namespace std;
 
// Function to find the absolute value
void findAbsolute(int N)
{
 
    // If the number is less than
    // zero, then multiply by (-1)
    if (N < 0)
    {
        N = (-1) * N;
    }
 
    // Print the absolute value
    cout << " " << N;
}
 
// Driver Code
int main()
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
    return 0;
}
 
// This code is contributed by shivanisinghss2110

C




// C program for Method 1
#include <stdio.h>
 
// Function to find the absolute value
void findAbsolute(int N)
{
 
    // If the number is less than
    // zero, then multiply by (-1)
    if (N < 0) {
        N = (-1) * N;
    }
 
    // Print the absolute value
    printf("%d ", N);
}
 
// Driver Code
int main()
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
    return 0;
}

Java




// Java program for Method 1
class GFG{
     
// Function to find the absolute value
static void findAbsolute(int N)
{
 
    // If the number is less than
    // zero, then multiply by (-1)
    if (N < 0)
    {
        N = (-1) * N;
    }
 
    // Print the absolute value
    System.out.printf("%d ", N);
}
 
// Driver Code
public static void main(String[] args)
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
}
}
 
// This code is contributed by 29AjayKumar

Python3




# Python3 program for Method 1
 
# Function to find the absolute value
def findAbsolute(N):
 
    # If the number is less than
    # zero, then multiply by (-1)
    if (N < 0):
        N = (-1) * N;
     
    # Print the absolute value
    print(N);
 
# Driver code
if __name__ == '__main__':
 
    # Given integer
    N = -12;
 
    # Function call
    findAbsolute(N);
 
# This is code contributed by amal kumar choubey

C#




// C# program for Method 1
using System;
using System.Collections.Generic;
 
class GFG{
     
// Function to find the absolute value
static void findAbsolute(int N)
{
 
    // If the number is less than
    // zero, then multiply by (-1)
    if (N < 0)
    {
        N = (-1) * N;
    }
 
    // Print the absolute value
    Console.Write("{0} ", N);
}
 
// Driver Code
public static void Main(String[] args)
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
}
}
 
// This code is contributed by sapnasingh4991

Javascript




<script>
    // Javascript program for Method 1
     
    // Function to find the absolute value
    function findAbsolute(N)
    {
 
        // If the number is less than
        // zero, then multiply by (-1)
        if (N < 0) 
        {
            N = (-1) * N;
        }
 
        // Print the absolute value
        document.write(" " + N);
    }
 
     
    // Given integer
    let N = -12;
   
    // Function call
    findAbsolute(N);
     
    // This code is contributed by suresh07.
</script>
Output: 



12

 

Method 2 – Using Bitmasking: Since negative numbers are stored in 2s complement form, to get the absolute value, we have to toggle bits of the number and add 1 to the result. Below are the steps: 
 

  1. Set the mask as right shift of integer by 31 (assuming integers are stored using 32 bits). 
     
mask = n >> 31
  1.  
  2. For negative numbers, above step sets mask as 1 1 1 1 1 1 1 1 and 0 0 0 0 0 0 0 0 for positive numbers. Add the mask to the given number. 
     
mask + n
  1.  
  2. XOR of mask +n and mask gives the absolute value. 
     
(mask + n)^mask 
  1.  

 

C++




// C++ program for Method 2
#include <bits/stdc++.h>
using namespace std;
#define CHAR_BIT 8
 
// Function to find the absolute
// value
void findAbsolute(int N)
{
 
    // Find mask
    int mask = N >> (sizeof(int) * CHAR_BIT - 1);
 
    // Print the absolute value
    // by (mask + N)^mask
    cout << ((mask + N) ^ mask);
}
 
// Driver Code
int main()
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
    return 0;
}
 
// This code is contributed by Code_Mech

C




// C program for Method 2
#include <stdio.h>
#define CHAR_BIT 8
 
// Function to find the absolute
// value
void findAbsolute(int N)
{
 
    // Find mask
    int mask
        = N
          >> (sizeof(int) * CHAR_BIT - 1);
 
    // Print the absolute value
    // by (mask + N)^mask
    printf("%d ", (mask + N) ^ mask);
}
 
// Driver Code
int main()
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
    return 0;
}

Java




// Java program for Method 2
class GFG{
     
static final int CHAR_BIT = 8;
 
// Function to find the absolute value
static void findAbsolute(int N)
{
 
    // Find mask
    int mask = N >> (Integer.SIZE / 8 *
                         CHAR_BIT - 1);
 
    // Print the absolute value
    // by (mask + N)^mask
    System.out.printf("%d ", (mask + N) ^ mask);
}
 
// Driver Code
public static void main(String[] args)
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
}
}
 
// This code is contributed by 29AjayKumar

Python3




# Python3 program for Method 2
import sys
 
CHAR_BIT = 8;
 
# Function to find the absolute value
def findAbsolute(N):
     
    # Find mask
    mask = N >> (sys.getsizeof(int()) // 8 *
                              CHAR_BIT - 1);
 
    # Print the absolute value
    # by (mask + N)^mask
    print((mask + N) ^ mask);
 
# Driver Code
if __name__ == '__main__':
     
    # Given integer
    N = -12;
 
    # Function call
    findAbsolute(N);
 
# This code is contributed by 29AjayKumar

C#




// C# program for Method 2
using System;
 
class GFG{
     
static readonly int CHAR_BIT = 8;
 
// Function to find the absolute value
static void findAbsolute(int N)
{
     
    // Find mask
    int mask = N >> (sizeof(int) / 8 *
                        CHAR_BIT - 1);
 
    // Print the absolute value
    // by (mask + N)^mask
    Console.Write((mask + N) ^ mask);
}
 
// Driver Code
public static void Main(String[] args)
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
}
}
 
// This code is contributed by 29AjayKumar
Output: 
12

 

Method 3 – Using inbuilt abs() function: The inbuilt function abs() in stdlib.h library finds the absolute value of any number.
Below is the implementation of the above approach: 
 

C++




// C++ program for Method 3
# include<bits/stdc++.h>
using namespace std;
 
// Function to find the absolute
// value
void findAbsolute(int N)
{
 
    // Find absolute
    int X = abs(N);
 
    // Print the absolute value
    cout << X;
}
 
// Driver Code
int main()
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
    return 0;
}
 
// This code is contributed by Nidhi_biet

C




// C program for Method 3
 
#include <stdio.h>
#include <stdlib.h>
 
// Function to find the absolute
// value
void findAbsolute(int N)
{
 
    // Find absolute
    int X = abs(N);
 
    // Print the absolute value
    printf("%d ", X);
}
 
// Driver Code
int main()
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
    return 0;
}

Java




// Java program for Method 3
class GFG{
     
// Function to find the absolute
// value
static void findAbsolute(int N)
{
 
    // Find absolute
    int X = Math.abs(N);
 
    // Print the absolute value
    System.out.printf("%d", X);
}
 
// Driver Code
public static void main(String[] args)
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
}
}
 
// This code is contributed by sapnasingh4991

Python3




# Python3 program for Method 3
import math
 
# Function to find the absolute
# value
def findAbsolute(N):
 
    # Find absolute
    X = abs(N);
 
    # Print the absolute value
    print(X);
 
# Driver Code
 
# Given integer
N = -12;
 
# Function call
findAbsolute(N);
 
# This code is contributed by Nidhi_biet

C#




// C# program for Method 3
using System;
 
class GFG{
     
// Function to find the absolute
// value
static void findAbsolute(int N)
{
 
    // Find absolute
    int X = Math.Abs(N);
 
    // Print the absolute value
    Console.Write("{0}", X);
}
 
// Driver Code
public static void Main(String[] args)
{
 
    // Given integer
    int N = -12;
 
    // Function call
    findAbsolute(N);
}
}
 
// This code is contributed by 29AjayKumar

Javascript




<script>
    // Javascript program for Method 3
     
    // Function to find the absolute
    // value
    function findAbsolute(N)
    {
 
        // Find absolute
        let X = Math.abs(N);
 
        // Print the absolute value
        document.write(X);
    }
     
    // Given integer
    let N = -12;
  
    // Function call
    findAbsolute(N);
 
</script>
Output: 
12

 

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