c语言编写 阶乘累加

Question

1！+2！+3！·····20！=？

Answer 1

#include<stdio.h>
long cal(int i)
{
long s;
int j;
for(j=1,s=1;j<=i;j++)
s=s*j;
return s;
}
main()
{
int i;
long sum=0;
for(i=1;i<=3;i++)
sum+=cal(i);
printf("%d\n",sum);
}
这个是c语言编程的程序，我已经在vc里面通过调试了，1楼的好像写的c++的程序吧

Answer 2

long acculater(long n){
long sum=1;
if (n==1)
{
return 1;
}
for(int i=1;i<=n;i++){
sum*=i;

}
sum+=acculater(n-1);
return sum;
}
用了递归 效率可能不高

Answer 3

#include "stdio.h"
main()
{int i,j,sum1,sum=0,n;
for(i=1;i<=20;i++)
{sum1=1;
for(j=1;j<=i;j++)
{
sum1=sum1*j;
}
sum=sum+sum1;
}
printf("1——20阶乘的和为:%d",sum);
}

Answer 4

long int jiecheng(int a)
{
long int m = 1;
do{
m *= a;
a--;
}while(a > 0);
return m;
}

int main()
{
long int sum = 0;
for(int i = 1; i <= 20; i++)
{
sum += jiecheng(i);
}
cout << sum;
return 0;
}

Answer 5

#include <stdio.h>

int jiecheng(int n){
if(n==1)
return 1;
else
return n*jiecheng(n-1);
}

int main(){
int i,result=0;
for(i=1;i<=20;i++){
result=result+jiecheng(i);
}
printf("%d\n",result);
return 0;
}