find out the pair of elements which are near to the given sum. This means the difference between the sum of elements of the pair and the given sum should be minimum. code example

Example: find pair in unsorted array which gives sum x

// C++ program to check if given array 
// has 2 elements whose sum is equal 
// to the given value 
  
#include <bits/stdc++.h> 
using namespace std; 
  
// Function to check if array has 2 elements 
// whose sum is equal to the given value 
bool hasArrayTwoCandidates(int A[], int arr_size, 
                           int sum) 
{ 
    int l, r; 
  
    /* Sort the elements */
    sort(A, A + arr_size); 
  
    /* Now look for the two candidates in  
       the sorted array*/
    l = 0; 
    r = arr_size - 1; 
    while (l < r) { 
        if (A[l] + A[r] == sum) 
            return 1; 
        else if (A[l] + A[r] < sum) 
            l++; 
        else // A[i] + A[j] > sum 
            r--; 
    } 
    return 0; 
} 
  
/* Driver program to test above function */
int main() 
{ 
    int A[] = { 1, 4, 45, 6, 10, -8 }; 
    int n = 16; 
    int arr_size = sizeof(A) / sizeof(A[0]); 
  
    // Function calling 
    if (hasArrayTwoCandidates(A, arr_size, n)) 
        cout << "Array has two elements with given sum"; 
    else
        cout << "Array doesn't have two elements with given sum"; 
  
    return 0; 
}