随机生成30道四则运算

//李妍 2015.3.4
//四则运算 
#include<iostream>
#include<string>
#include<stdlib.h>
#include<time.h>
using namespace std;
void main()
{
    srand((unsigned)time(NULL));//设置时间种子 ，以使程序每次得到的结果都不同 
    for (int i = 0; i < 30; i++)
    {
       int a,b,c;
       int fenmu_1, fenmu_2;
       //生成第一个操作数
       a = (rand() %(100))+1 ;
       if (a == 100)
       {
           a = (rand() % 99)+1;
           fenmu_1 = a + (rand() %( 99-a+1));
           cout << "(" << a << "/" << fenmu_1 << ")";
        }
       else cout << a;
       
       //随机生成运算符
       char o;
       c= (rand() % 100)%4;
       if (c == 0) o = ‘+‘;
       else if (c == 1) o = ‘-‘;
       else if (c == 2) o = ‘*‘;
       else o = ‘/‘;
       cout << o;
       //生成第二个操作数
       b = 1+rand() % (100);
       if (b == 100)
       {
           b = (rand() % 99)+1;
           fenmu_2 = b + (rand() % (99-b+1));
           cout << "(" << b << "/" << fenmu_2 << ")";
        }
       else cout << b;
       cout << "=";
       cout << endl;
    }

}