Question

如何用C语言编程1!+2!+3!+4!+.....+20!

Answer 1

#include<stdio.h>
void main()
{
int sum=0,k=1;i,j,;
for(i=1;i<=20,i++)
{
for(j=1;j<=i,j++)
k=k*j;
sum=sum+k;
}
printf("%d",sum);
}

Answer 2

#include<stdio.h>
void main()
{
int fac(int n);
int i,m=0;
for(i=1;i<=20;i++)
m+=fac(i);
printf("%d\n",m);
}
int fac(int n)
{
static int f=1;
f*=n;
return(f);
}

Answer 3

#include<stdio.h>
main()
{
int i,j,a=1;
long sum=0;

for(i=1;i<=20;i++)
{
for(j=1;j<=i;j++)
{
a=a*j;
}
sum=sum+a;
a=1;

}
printf("sum=\%d\n",sum);
}

Answer 4

#include<stdio.h>
void main()
{int s=0,i;
for(i=1;i<=20;i++)
{s=s+i;}
printf("%d",s);
}

Answer 5

long long fun(int a)
{
if (1 == a)
{
return 1;
}

return a * fun(a - 1);
}

int main()
{
long long tmp = 0;
for (int i = 1; i <= 20; i++)
{
tmp += fun(i);
}
cout << tmp << endl;
}