10以内的数字的四则运算

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
int main()
{
int num1,num2,op,result1,result2; //num1,num2:操作数;op：运算符;result1,result2:结果
do
{
srand(time(NULL));
num1=rand()*10/(RAND_MAX+1);
num2=rand()*10/(RAND_MAX+1); //生成运算数
op=rand()*4/(RAND_MAX+1); //生成运算符 0-- +，1-- -，2-- *，3-- /

switch (op)
{
case 0:
cout<<num1<<"+"<<num2<<"=? ";
cin>>result1;
if (num1+num2 == result1)
cout<<"you are right"<<endl;
else
cout<<"you are wrong"<<endl;
break;
case 1:
cout<<num1<<"-"<<num2<<"=? ";
cin>>result1;
if (num1-num2 == result1)
cout<<"you are right"<<endl;
else
cout<<"you are wrong"<<endl;
break;
case 2:
cout<<num1<<"*"<<num2<<"=? ";
cin>>result1;
if (num1*num2 == result1)
cout<<"you are right"<<endl;
else
cout<<"you are wrong"<<endl;
break;
case 3:
cout<<num1<<"/"<<num2<<"=? ";
cin>>result1;
cout<<"余数为=? ";
cin>>result2;
if ((num1/num2 == result1)&&(num1%num2==result2))
cout<<"you are right"<<endl;
else
cout<<"you are wrong"<<endl;
break;
}
}while(1);
return 0;

}