long和int有啥区别?
#include<stdio.h>
//编写函数
/Begin/
long long fac(int n)
{
long a,b;
long sum=0,x=1;
for(a=1;a<=n;a++)
{
for(b=1;b<=a;b++)
{
x=x*b;
}
sum=sum+x;
x=1;
}
return sum;
}
/End/
int main(void)
{
/Begin/
int n;
scanf("%d",&n);
if(n>=1&&n<=20)
{
printf("%lld",fac(n));
}
else
{
printf("错误");
}
/End/
return 0;
}
这个里面的long能换成int不?