课后作业1

package 四则运算;

import java.util.Random;

public class FourOperations {
    public static void main(String args[])
    {
        String firstNumber = null,secondNumber = null;
        Random random=new Random();
        
        for(int i=0;i<20;i++)
        {
            int temp=Math.abs(random.nextInt()%2);
            if(temp==1)
            {
                 firstNumber="("+String.valueOf(Math.abs(random.nextInt()%100))+"/"+String.valueOf(Math.abs(random.nextInt()%100)+")");
                 secondNumber="("+String.valueOf(Math.abs(random.nextInt()%100))+"/"+String.valueOf(Math.abs(random.nextInt()%100)+")");
            }
            else
            {
                int f=random.nextInt();
                firstNumber=String.valueOf(Math.abs(f%100));
                int s=random.nextInt();
                secondNumber=String.valueOf(Math.abs(s%100));
            }
            char fuhao[]={‘+‘,‘-‘,‘*‘,‘/‘};
            int k=random.nextInt();
            int demp=Math.abs(k%4);
            switch(fuhao[demp])
            {
             case ‘+‘:
            {
                System.out.println(firstNumber+"+"+secondNumber+"=");
            }break;
             case ‘-‘:
             {
                System.out.println(firstNumber+"-"+secondNumber+"=");
             }break;
             case ‘*‘:
             {
                System.out.println(firstNumber+"*"+secondNumber+"=");
             }break;
             case ‘/‘:
             {
                 if(secondNumber!="0")
                 {
                    System.out.println(firstNumber+"/"+secondNumber+"=");
                 }    
             }
            }
        }
    }

}