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Program to find absolute value of a given number

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  • Difficulty Level : Basic
  • Last Updated : 14 Sep, 2022
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Given an integer N, The task is to find the absolute value of the given integer.

Examples: 

Input: N = -6 
Output: 6
Explanation: The absolute value of -6 is 6 which is non negative

Input: N = 12 
Output: 12 

Naive Approach: To solve the problem follow the below idea:

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

Below is the implementation of the above approach.

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

Time Complexity: O(1)
Auxiliary Space: O(1)

Find the absolute value of a given number Using Bitmasking

To solve the problem follow the below idea:

Negative numbers are stored in the form of 2s complement, to get the absolute value we have to toggle bits of the number and add 1 to the result. 

Follow the steps below to implement the idea: 

  • Set the mask as right shift of the integer by 31 (assuming integers are stored using 32 bits) mask = n >> 31
  • 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 i.e. mask + n   
  • XOR of mask + n and mask gives the absolute value i.e. (mask + n)^mask    

Below is the implementation of the above approach.

C++




// C++ program for above approach
 
#include <bits/stdc++.h>
using namespace std;
 
// 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

Javascript




<script>
    // Javascript program for Method 2
     
    let CHAR_BIT = 8;
  
    // Function to find the absolute value
    function findAbsolute(N)
    {
 
        // Find mask
        let mask = N >> (4 / 8 * CHAR_BIT - 1);
 
        // Print the absolute value
        // by (mask + N)^mask
        document.write((mask + N) ^ mask);
    }
     
    // Given integer
    let N = -12;
  
    // Function call
    findAbsolute(N);
 
// This code is contributed by mukesh07.
</script>

Output

12

Time Complexity: O(1)
Auxiliary Space: O(1)

Find the absolute value of a given number Using the inbuilt abs() function:

To solve the problem follow the below idea:

The inbuilt function abs() in stdlib.h library finds the absolute value of any number. This can be used to find absolute value of any integer.

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

Time Complexity: O(1)
Auxiliary Space: O(1)


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