P111例4-28程序 #include <stdio. h> maino [int i, n; double term, sum; prnf(“ please input n:")冫 scant%d”,&n) 递推法! for(i=1, term=1, sum=0; i<=n; i++l 求还可以怎 i term"=i- 样求? sum=sum+term 找规律(通项)* prnf(“sum=%fn,sum)7 P111例4－28程序一 #include <stdio.h> main() {int i,n; double term,sum; printf(“please input n:”); scanf(“%d”,&n); for(i=1,term=1,sum=0;i<=n;i++) { term*=i; sum=sum+term; } /* 找规律（通项） */ printf(“sum=%lf\n”,sum); } •递推法！ •求i!还可以怎 样求？