自动生成小学四则运算题

要求：

 

 

import java.util.Random;
import java.util.Scanner;
public class Math2 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in=new Scanner(System.in);
        Random r = new Random();
        int i,j,n;
        n=in.nextInt();
        int size=1000;
        int [] a1=new int[size];
        int [] a2=new int[size];
        int [] t=new int[size];
        for(i=0;i<n;i++)
        {
            a1[i]=r.nextInt(99)+1;
            a2[i]=r.nextInt(99)+1;
            t[i]=r.nextInt(100)%4;
            for(j=0;j<i;j++)
            {
                while(a1[i]==a1[j]&&a2[i]==a2[j]&&t[i]==t[j]) {   //避免重复
                    t[i]=(t[i]*4+1)%4;
                    a1[i]=r.nextInt(99)+1;
                    a2[i]=r.nextInt(99)+1;
                }
            }
            switch(t[i])
            {
                case 0:System.out.println(a1[i]+"+"+a2[i]+"=");break;
                case 1:System.out.println(a1[i]+"-"+a2[i]+"=");break;
                case 2:System.out.println(a1[i]+"*"+a2[i]+"=");break;
                case 3:System.out.println(a1[i]+"/"+a2[i]+"=");break;
            }
        }    
    }
}