C - Remove Duplicate Results in Recursive Function

Question

I have to create a recursive function that tells you the number of ways a number of cents can be made into change. (Using quarters, dimes nickels, and pennies).

So f

Answer 1

#include <stdio.h>

int coins(int, int);

int main(void){
    int num;

    printf("Enter an amount of change in cents: ");
    scanf("%d", &num);

    printf("There are %d ways to make change for %d cents.\n", coins(num, 0), num);
    return 0;
}

int coins(int amt, int kind){
    static int kinds[4] = {25, 10, 5, 1};
    int ways=0, i, n;

    if(kinds[kind] == 1)//always divisible
        return 1;

    n = amt / kinds[kind];
    for(i = 0; i <= n; ++i)
        ways+=coins(amt-kinds[kind]*i, kind + 1);

    return ways;
}