随机四则运算

package hu;
import java.util.Scanner;
public class Hu
{
    
    public static void main(String[] args)
    {
        String x = null;
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入题目的总数：");
        int count=sc.nextInt();
        System.out.println("请输入每行的题目数：");
        int math=sc.nextInt();
        int stra[]=new int[100000];
        int strb[]=new int[100000];
        int flag=1;
        for(int i=1;i<=count;i++)
        {
            int a=(int)(1+Math.random()*99);
            int b=(int)(1+Math.random()*99);
            int c=(int)(1+Math.random()*4);
            stra[i]=a;
            strb[i]=b;
            switch(c)
            {
            case 1:x="+";break;
            case 2:x="-";break;
            case 3:x="*";break;
            case 4:x="/";break;
            }
            for(int j=0;j<i;j++)
            {
                if(stra[j]==stra[i]&&strb[j]==strb[i])
                    flag=0;
                else
                    flag=1;
            }
            if(flag==1)
            {
                     if(a>=b&&(a%b)==0&&a*b<=100) 
                     System.out.print(i+":"+a+x+b+"="+"      ");
                     else 
                     {
                         i--;
                         continue;
                     }
               if(i%math==0)
            System.out.println();
            }
        }
    }
}