#include<iostream>

#include<time.h>

#include<stdlib.h>

using namespace std;

void main(){

int t,num,a,n,i,b,k,s,r;

int score=0;

cout<<" "<<endl;

 srand(time(NULL));

for(i=1;i<=30;i++)

{

a=rand()%100;

loop: b=rand()%100;

n=rand()%4;

switch(n)

{

case 0:cout<<""<<i<<""<<endl;

cout<<a<<"+"<<b<<"="; t=a+b;

break;

case 1:cout<<""<<i<<""<<endl;

 cout<<a<<"-"<<b<<"="; t=a-b; break;

case 2:cout<<""<<i<<""<<endl;

 cout<<a<<"*"<<b<<"="; t=-a*b; break;

case 3:cout<<""<<i<<""<<endl;

 cout<<""<<i<<""<<endl;cout<<a<<"/"<<b<<"=";

if(b==0) goto loop; t=a/b; break;}

int cnt=3;

do{

cin>>num;

if(num==t)

{

cout<<"正确"<<endl;}

else

{

if(cnt<3)

cout<<"错误"<<endl;

cout<<"你还有"<<3-cnt<<"次答题机会"<<endl;

++cnt;}

}while(cnt<=3&&num!=t);

if(num!=t)

cout<<"错误！正确答案是:"<<t<<endl;

switch(cnt)

{

case 1:score+=10;break;

case 2:score+=7;break;

case 3:score+=5;break;}

cout<<"当前分数为"<<score<<endl;}

cout<<"最后得分"<<score<<"";}