Java小demo-简单计算器

• 需求：写个计算器，能完成加减乘除运算

  • 定义接口做参数
  • 加减乘除定义4个类
  • 定义一个静态工具类，把下面的接口作为其中一个形参对象，传递具体的运算符类完成计算

• 定义一个接口

public interface IComputer {
    int compute(int num1, int num2);
}

• 定义加减乘除4个类

public class AddOper implements IComputer {
    @Override
    public int compute(int num1, int num2) {
        return num1 + num2;
    }
}

public class SubOper implements IComputer {
    @Override
    public int compute(int num1, int num2) {
        return num1 - num2;
    }
}

public class MulOper implements IComputer {
    @Override
    public int compute(int num1, int num2) {
        return num1 * num2;
    }
}

public class DivideOper implements IComputer {

    @Override
    public int compute(int num1, int num2) {
        try {
            return num1 / num2;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return -1;
    }
}

• 定义一个静态工具类

public class UserComputer {
    public static void compute(IComputer computer, int num1, int num2) {
        System.out.println(computer.compute(num1, num2));
    }

    public static void main(String[] args) {
        UserComputer.compute(new AddOper(), 1, 2);
        UserComputer.compute(new SubOper(), 1, 2);
        UserComputer.compute(new MulOper(), 1, 2);
        UserComputer.compute(new DivideOper(), 1, 2);
    }
}