编写c语言函数计算从n个元素中取m个元素的组合数C（m，n）；要求：输入n和m为整型，m<=n，用

#include int ifac(int n);int nCr(int n, int r);int main(void) { int a, b, result; printf("Input two numbers: "); scanf("%d%d", &a, &b); result = nCr(a, b); if (result == 0) printf("Wrong!\n"); else print