C(m,n) and P(m,n)

c_p_mn.c

#include<stdio.h>
void c_p_mn_array(int m, int n, int result[2]) {
    int i;
    result[1] = 1;
    for (i=m-n+1; i<=m; i++)
        result[1] *= i;
    result[0] = result[1];
    for (i=2; i<=n; i++)
        result[0] /= i;
}
void c_p_mn_pointer(int m, int n, int *c, int *p) {
    int i;
    *p = 1;
    for (i=m-n+1; i<=m; i++)
        *p *= i;
    *c = *p;
    for (i=2; i<=n; i++)
        *c /= i;
}
struct cp {
    int c;
    int p;
};
struct cp c_p_mn_struct(int m, int n) {
    struct cp ans;
    int i;
    ans.p = 1;
    for (i=m-n+1; i<=m; i++)
        ans.p *= i;
    ans.c = ans.p;
    for (i=2; i<=n; i++)
        ans.c /= i;
    return ans;
}
int main() {
    int m, n;
    int result[2];
    int combination, permutation;
    struct cp ans;
    scanf("%d%d", &m, &n);
    c_p_mn_array(m, n, result);
    printf("%d %d\n", result[0], result[1]);
    c_p_mn_pointer(m, n, &combination, &permutation);
    printf("%d %d\n", combination, permutation);
    ans = c_p_mn_struct(m, n);
    printf("%d %d\n", ans.c, ans.p);
    return 0;
}