#include<stdio.h>
int main()
{
void f1();
void f2();
void f3();
while(1)
{
int a;
scanf("%d",&a);
switch(a)
{
case 1:f1();break;
case 2:f2();break;
case 3:f3();break;
}
}
}
void f1( )
{
int a,x;
scanf("%d",&x);
for(a=2;a<x+1;a++){
if(x%a==0)
break;}
if(a==x)
printf("是");
else
printf("否");
}
void f2()
{
int a,b,c,y;
scanf("%d",&y);
a=y/100;
b=(y-100a)/10;
c=y%10;
if(y=aaa+bbb+cc*c)
printf(" 是");
else
printf(" 否");
}
void f3()
{
int x,y,z;
char c;
scanf("%d%s%d",&x,&c,&y);
switch(c)
{
case '+':z=x+y;printf("%d",z);break;
case '-': z=x-y;printf("%d",z);break;
}
}
%s改%c
scanf("%d%s%d",&x,&c,&y);
改为
scanf("%d%c%d",&x,&c,&y);
c被声明为字符型，需要用%c，%s用来格式化字符串。