编程计算S= 1!/(1+2)+ 2!/(1+2+3)+ 3!/(1+2+3+4) + …. + 20!/(1+2+3+4+…..+21)

#include "stdio.h" float fac1( int x) {if(x==1)return 1; else return x*fac1(x-1); } float fac2(int y) {int sum=0,i; for(i=1;i<=y;i++) sum+=i; return sum; } int main() { float result=0.0; int a; for(a=1;a<=12;a++