Program-To find find all pairs of  elements from an array whose sum is equal to given number  

1. class SumIsEqualTo
2. {
3. public static void main(String args[])
4. {
5. int array[]={18,4,6,12,20,16};
6. 
   
7. sumEquals(array,22);
8. }
9. public static  void sumEquals(int arr[],int X)
10. {
11. if(arr.length<2)
12.     return;
13. 
    
14.    System.out.println("the set or pairs of number whose sum is equals to 22 are :");
15. 
    
16. for(int i=0;i<arr.length;i++)
17. {
18. for(int j=1+i;j<arr.length;j++)
19. {
20. int temp=arr[i] + arr[j];
21. if(temp==X)
22. {
23. System.out.println(arr[i] +","+arr[j]);
24. }
25. }
26. }
27. }
28. }    

     For example:

                                            Given a  array,we need to find all pairs whose sum is equal to number X (In           above program X=22)                         

1. array[]={18,4,6,12,20,16};
3. Pair of elements whose sum is equal to 22 :  18, 4 and 6,16.