简单四则运算的随机输入

java练习

课堂练习题目，随机输入一个简单的四则运算，符号也随机，不输出结果。

代码：

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String[] number = {"0","1","2","4","5","6","7","8","9","10","11","12","13","14","15","16","17","18","19","20","21","22","23","24","25","26","27","28","29"};
        String[] fuhao = {"+","-","*","/"};
        
        int oneLength = number.length;
        int twoLength = fuhao.length;
        int threeLength = number.length;
        
        int rand1 = (int) (Math.random() * oneLength);
        int rand2 = (int) (Math.random() * twoLength);
        int rand3 = (int) (Math.random() * threeLength);
        
        String phrase = number[rand1] + " " +fuhao[rand2] + " " + number[rand3];
        
        System.out.println("四则运算试为 " + phrase + " = ");
    }

数字是手动输入的，因此对代码做改进：

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String[] fuhao = {"+","-","*","/"};
        
        int twoLength = fuhao.length;
        
        int rand1 = (int) (Math.random() * 99);
        int rand2 = (int) (Math.random() * twoLength);
        int rand3 = (int) (Math.random() * 99);
        
        String phrase = rand1 + " " +fuhao[rand2] + " " + rand3;
        
        System.out.println("四则运算试为 " + phrase + " = ");
    }

总结:java编程实践过少