随机生成30道四则运算题NEW

代码：

#include <iostream>
#include <time.h>
using namespace std;

void main()
{ 
    srand((int)time(NULL));     //每次执行种子不同，生成不同的随机数
    int a, b, c, d, e, i, mark,opt;
    for (i = 0; i < 30; i++)
    {
        opt = 1 + rand() % 2;//随机生成1或者2来表示整数和真分数
        a = 1 + rand() % 100;//将1到100内的数随机赋予a
        b = 1 + rand() % 100;//将1到100内的数随机赋予b
        c = 1 + rand() % 100;//将1到100内的数随机赋予c
        d = 1 + rand() % 100;//将1到100内的数随机赋予d
        if (opt == 1)
        {
            mark = 1 + rand() % 4;//随机生成1-4来分别表示四个运算符
            cout << a;
            switch (mark)
            {
            case 1:cout << "+"; break;
            case 2:cout << "-"; break;
            case 3:cout << "×"; break;
            case 4:cout << "÷"; break;
            }
            cout << b << "=" << endl;
        }
        if (opt == 2)
        {
            if (a > b)
            {
                e = a;
                a = b;
                b = e;
            }
            cout << "(" << a << "/" << b <<")";
            mark = 1 + rand() % 4;
            switch (mark)
            {
            case 1:cout << "+"; break;
            case 2:cout << "-"; break;
            case 3:cout << "×"; break;
            case 4:cout << "÷"; break;
            }
            if (c > d)
            {
                e = c;
                c = d;
                d = e;
            }
            cout << "(" << c << "/" << d << ")" <<"="<< endl;
        }
        
    }
}