SUM

//Given an array of n elements. Find two elements in the array such that their sum is equal to given element k

# include <stdio.h>
#include<stdlib.h>
# define bool int
 
void quickSort(int *, int, int);
 
bool hasArray(int A[], int arr_size, int sum)
{
    int l, r;                   
    quickSort(A, 0, arr_size-1);                            //Sorting the elements of the array using quick sort
    l = 0;
    r = arr_size-1; 
    while (l < r)
    {
         if(A[l] + A[r] == sum)
	 {
               
	         printf("The numbers that add up to given element are : %d and %d",A[l],A[r]);
		 return 1;
	 } 
         else if(A[l] + A[r] < sum)
              l++;
         else // A[i] + A[j] > sum
              r--;
    }    
    return 0;
}
 

void exchange(int *a, int *b)                                // Function for swapping the elements
{
    int temp;
    temp = *a;
    *a   = *b;
    *b   = temp;
    
    
    
}
 
int partition(int A[], int si, int ei)
{
    int x = A[ei];
    int i = (si - 1);
    int j;
 
    for (j = si; j <= ei - 1; j++)
    {
        if(A[j] <= x)
        {
            i++;
            exchange(&A[i], &A[j]);
        }
    }
    exchange (&A[i + 1], &A[ei]);
    return (i + 1);
}
 
void quickSort(int A[], int si, int ei)                       //Quick sort
{
    int pi;                                                   //Partitioning index
    if(si < ei)
    {
        pi = partition(A, si, ei);
        quickSort(A, si, pi - 1);
        quickSort(A, pi + 1, ei);
    }
}
 
int main()
{

	int sum;
        int n;
        int *array;
        printf("Enter the no. of elements");
        scanf("%d",&n);
        array=calloc(n,sizeof(int));
        printf("Enter the elements ");
        for(int i=0;i<n;i++)
        {
        scanf("%d",(array+i));
        }
	printf("Enter the sum ");
	scanf("%d",&sum);
      if(hasArray(array,n,sum))
        printf("\nArray has two elements with given sum");
    else
        printf("\nArray doesn't have two elements with given sum");
 
    return 0;
}