PTA-求组合数（C语言）
#include<stdio.h>
double fact(int num){
double result=num;
for(int i=num-1;i>0;i--){
result*=i;
}
return result;
}
int main(){
int num1=0,num2=0;
double a=0,b=0,c=0;
double result=0;
scanf("%d %d",&num1,&num2);
if(num1==num2){
printf("result = 1");
}else{
a=fact(num2);
b=fact(num1);
c=fact(num2-num1);
printf("result = %1.0f",a/(b*c));
}
return 0;
}