Count pairs with a given sum

Given an array of integers, and a number ‘sum’, find the number of pairs of integers in the array whose sum is equal to ‘sum’.

Program:

public class pair_sum {

public static void main(String args[])

{

    int a[]={3,4,2,6,5,2,1};

    int n=a.length;

    int sum=7;

    for(int i=0;i<n-1;i++)

    {

        int first=a[i];

        for(int j=i+1;i<n;j++)

        {

            int second=a[j];

            if((first+second)==sum)

            {

                System.out.println("The pair of elemnets are"+first +" " +second);

                

            }

        }

    }

}

}

OUTPUT:

The pair of elemnets are3 4