package common;

import java.util.*;

public class Cacluter {
 public interface MathOperation {
 double op(double a, double b);
 }
 private static Map<String, MathOperation> mathOperationMap = new HashMap<>();
 static {
 mathOperationMap.put("+", new MathOperation() {
 @Override
 public double op(double a, double b) {
 return a + b;
 }
 });
 mathOperationMap.put("-", (a, b) -> { return a-b; });
 mathOperationMap.put("*", (a, b) -> a*b);
 mathOperationMap.put("/", (a, b) -> a/b);
 mathOperationMap.put("%", (a, b) -> a%b);
 // 作业,加计算乘方的运算符 ^
 }

 public static void main(String[] args) {
 System.out.println("输入算式,运算符,运算数用空格分割:");
 Scanner in = new Scanner(System.in);
 double a = in.nextDouble();
 String op = in.next();
 double b = in.nextDouble();
 MathOperation mop = mathOperationMap.get(op);
 if (mop == null) {
 System.out.println("不支持的运算符:" + op);
 return;
 }
 double r = mop.op(a, b);
 System.out.println(a + op + b + " = " + r);
 }


}