Java—switch case实现两个数的算术运算

小鱼儿 2024-02-17 17:44 10阅读 0赞

方法一：

package com.liaojianya.chapter1;
    
    import java.util.Scanner;
    
    public class SwitchDemo1
    {
    	public static void main(String[] args)
    	{
    		Scanner input = new Scanner(System.in);
    		System.out.println("Enter number a : ");
    		double a = input.nextDouble();
    		System.out.println("Enter number b : ");
    		double b = input.nextDouble();
    		Action ac = new Action(a, b);
    		ac.command(Action.ADD);
    		ac.command(Action.SUBTRACT);
    		ac.command(Action.MULTIPLY);
    		ac.command(Action.DIVIDE);
    		ac.command(Action.MOD);
    		input.close();
    	}
    }
    
    class Action
    {
    	double a;
    	double b;
    	public Action(double a, double b)
    	{
    		this.a = a;
    		this.b = b;
    	}
    	public static final int ADD = 1;
    	public static final int SUBTRACT = 2;
    	public static final int MULTIPLY = 3;
    	public static final int DIVIDE = 4;
    	public static final int MOD = 5;
    
    	public void command(int c)
    	{
    		switch (c)
    		{
    		case 1:
    			System.out.println(a + " + " + b + " = " + (a + b));
    			break;
    
    		case 2:
    			System.out.println(a + " - " + b + " = " + (a - b));
    			break;
    
    		case 3:
    			System.out.println(a + " * " + b + " = " + (a * b));
    			break;
    
    		case 4:
    			System.out.println(a + " / " + b + " = " + (a / b));
    			break;
    
    		case 5:
    			System.out.println(a + " % " + b + " = " + (a % b));
    			break;
    
    		default:
    			System.out.println("unknown operation!");
    			break;
    		}
    	}
    
    }

方法二：

package com.liaojianya.chapter1;
    
    import java.util.Scanner;
    
    /**
     * This program demonstrates the use of switch.
     * @author LIAO JIANYA
     *
     */
    public class SwitchDemo
    {
    	public static void main(String[] args)
    	{
    		Scanner input = new Scanner(System.in);
    		
    		System.out.println("Enter number a : ");
    		double a = input.nextDouble();
    		System.out.println("Enter number b : ");
    		double b = input.nextDouble();
    		System.out.println("Enter  operater :1代表+，2代表-，3代表*，4代表/，5代表% ");
    		int c = input.nextInt();
    		switch(c)
    		{
    			case 1:
    			System.out.println(a + " + " + b + " = " + (a + b));
    			break;
    
    			case 2:
    			System.out.println(a + " - " + b + " = " + (a - b));
    			break;
    
    			case 3:
    			System.out.println(a + " * " + b + " = " + (a * b));
    			break;
    
    			case 4:
    			System.out.println(a + " / " + b + " = " + (a / b));
    			break;
    
    			case 5:
    			System.out.println(a + " % " + b + " = " + (a % b));
    			break;
    			
    			default:
    				System.out.println("unknown operation!");
    				break;
    		}
    	}
    
    }

运行结果：

Enter number a : 
    12.3
    Enter number b : 
    32.1
    12.3 + 32.1 = 44.400000000000006
    12.3 - 32.1 = -19.8
    12.3 * 32.1 = 394.83000000000004
    12.3 / 32.1 = 0.38317757009345793
    12.3 % 32.1 = 12.3