Question

C++中经典的“给小学生出加法考试题”

#include <iostream>
#include <stdlib.h>
int AddTest(int,int);
int AddTest(int a,int b)
{return a+b;}
using namespace std;
int main()
{
inti,a,b,c,d=0,e=0,f;
for(i=1;i<=10;i++)
{
a=rand()%10+1;
b=rand()%10+1;
cout<<a<<"+"<<b<<"="<<endl;
cout<<"Pleaseinput the corrcet result:"<<endl;
cin>>c;
f=AddTest(a,b);
if(c!=f)
{
cout<<"Notcorrect!"<<endl;
e=e+1;
}
else
{
cout<<"Right!"<<endl;
d=d+10;
}
}
cout<<"Thescore is:"<<d<<endl;
cout<<"Thewrong resluts are:"<<e<<endl;
return0;
}

以上是我自己写的，但是为什么每次系统出的题都是一样的呢？

Answer 1

在a=rand()%10+1;之前加上一句，产生随机数种子就可以了：
srand(unsigned(time(0)));

加个头文件：
#include <ctime>

http://zhidao.baidu.com/link?url=LkmrYvmEJlh77ZBf_mkURjtsjErhO2FGVQ6X1lmq51L8Je1bAM0vgalxNbb1sS1dU89lefngyoQTw9c5eRdVOa

Answer 2

#include <iostream>
#include <stdlib.h>
#include <time.h>
int AddTest(int,int);
int AddTest(int a,int b)
{return a+b;}
using namespace std;
int main()
{
int i,a,b,c,d=0,e=0,f;
for(i=1;i<=10;i++)
{
srand(time(NULL));
a=rand()%10+1;
b=rand()%10+1;
cout<<a<<"+"<<b<<"="<<endl;
cout<<"Pleaseinput the corrcet result:"<<endl;
cin>>c;
f=AddTest(a,b);
if(c!=f)
{
cout<<"Notcorrect!"<<endl;
e=e+1;
}
else
{
cout<<"Right!"<<endl;
d=d+10;
}
}
cout<<"Thescore is:"<<d<<endl;
cout<<"Thewrong resluts are:"<<e<<endl;
return 0;
}

Answer 3

字母表示(a+b）c=a+(b+c)