小白简易计算器

第一次尝试写代码

public class Calculator {
    public static void main(String[] args) {
        //创建扫描对象
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入第一个数据：");
        double a = scanner.nextDouble();
        System.out.println("请输入运算符：");
        String operator = scanner.next();
        System.out.println("请输入第二个数据：");
        double b = scanner.nextDouble();
        double result = 0;//储存结果
        //根据输入的运算符调用不同方法
        if ("+".equals(operator)) {// TODO equals 判断字符串是否相等
            result = add(a , b);
        }else if ("-".equals(operator)){
            result = sub(a , b);
        }else if ("*".equals(operator)){
            result = multiply(a , b);
        }else if ("/".equals(operator)){
            result = div(a , b);
        }else {
            System.out.println("输入错误");
        }
        System.out.println("结果为："+ result);
        scanner.close();//关闭
    }
    //+-*/
    public  static double add(double a, double b) {
        return a + b;
    }
    public static double sub(double a, double b) {
        return a - b;
    }
    public static double multiply(double a, double b) {
        return a * b;
    }
    public static double div(double a, double b) {
        return a / b;
    }
}