#include <stdio.h>

int count_combinations(
    int itemCosts[]
,   size_t costCount
,   int pickedItems[]
,   size_t pickedCount
,   size_t pickedTargetCount
,   size_t minIndex
,   int funds
) {
    if (pickedCount == pickedTargetCount) {
        // This is the base case. It has the code similar to
        // the "if" statement from your code, but the number of items
        // is not fixed.
        int sum = 0;
        for (size_t i = 0 ; i != pickedCount ; i++) {
            sum += pickedItems[i];
        }
        if (sum <= funds) {
        	for (size_t i = 0 ; i != pickedCount ; i++) {
                printf("%d ", pickedItems[i]);
            }
            printf("\n");
        }
        // The following line will return 0 or 1,
        // depending on the result of the comparison.
        return sum <= funds;
    } else {
        // This is the recursive case. It is similar to one of your "for"
        // loops, but instead of setting "one", "two", or "three"
        // it sets pickedItems[0], pickedItems[1], etc.
        int res = 0;
        for (size_t i = minIndex ; i != costCount ; i++) {
            pickedItems[pickedCount] = itemCosts[i];
            res += count_combinations(
                itemCosts
            ,   costCount
            ,   pickedItems
            ,   pickedCount+1
            ,   pickedTargetCount
            ,   i+1
            ,   funds
            );
        }
        return res;
    }
}


int main(void) {
	int itemCosts[] = {1, 3, 5, 7}; // The costs
    int pickedItems[2]; // No need to initialize this array
    int res = count_combinations(itemCosts, 4, pickedItems, 0, 2, 0, 8);
    printf("Got %d combinations\n", res);
	return 0;
}