combinations of sums

[kawa46]

Good Evening,

I write on this forum because i need help to solve the following problem in c: given n number, the program should write all the possible sums combinations of this numbers; for example if i have a b c, the program had to print a+b, a+c, a+b+c as result. On web i found this program

// Program to print all combination of size r in an array of size n
#include <stdio.h>
void combinationUtil(int arr[], int data[], int start, int end, int index, int r);

// The main function that prints all combinations of size r
// in arr[] of size n. This function mainly uses combinationUtil()
void printCombination(int arr[], int n, int r)
{
// A temporary array to store all combination one by one
int data[r];

// Print all combination using temprary array 'data[]'
combinationUtil(arr, data, 0, n-1, 0, r);

}

/* arr[] ---> Input Array
data[] ---> Temporary array to store current combination
start & end ---> Staring and Ending indexes in arr[]
index ---> Current index in data[]
r ---> Size of a combination to be printed */
void combinationUtil(int arr[], int data[], int start, int end, int index, int r)
{
// Current combination is ready to be printed, print it
if (index == r)
{
for (int j=0; j<r; j++)

printf("%d ", data[j]);
printf("\n");
return;
}

// replace index with all possible elements. The condition
// "end-i+1 >= r-index" makes sure that including one element
// at index will make a combination with remaining elements
// at remaining positions
for (int i=start; i<=end && end-i+1 >= r-index; i++)
{
data[index] = arr[i];
combinationUtil(arr, data, i+1, end, index+1, r);
}
}

// Driver program to test above functions
int main()
{
int arr[] = {1, 2, 3, 4};
int r=3;
int n = sizeof(arr)/sizeof(arr[0]);
for (int k=2; k<=r; k++)
printCombination(arr, n, k);

}


This program as result give:
1 2
1 3
1 4
2 3
.
.
1 2 3
1 2 4
ecc

I want that, near the numbers, will print the corresponding sum...Someone can help me? thank you and sorry for my english