int main(){
int n;int fact =1;;int i=1;
scanf ("%d", &i);
for (i=1; i<=n; i++){fact*=i;}
printf ("%d!= %d\n ",n ,fact );
return 0;
jie
scanf应该是要获取输入的值赋值给n吧,你写的赋值给i了。应该是 scanf("%d", &n);