Java 用键盘输入 int型 String型 char型数据 示例：简单计算功能 eclipse

版权声明：虽然我依旧蒟蒻，但请你尊重我 ：D　　　——陈杉菜 https://blog.csdn.net/qq_44702847/article/details/88226868

这里用一个有简单计算功能的java代码当例子
刚刚接触java啥都不会
菜里转型 干巴嘚

无注释版

import java.util.Scanner;

public class Calc {

	public int num1;
	public int num2;
	public double result=0.0;
	public char operation;
	public void calculate() {
		if(operation == '+')
			result=num1+num2;
		else if(operation == '-')
			result=num1-num2;
		else if(operation == '*')
			result=num1*num2;
		else if(operation == '/')
			if(num2 != 0)
				result=num1*1.0/num2;
			else 
				System.out.println("Incorrect input!");
		else
			System.out.println("Unrecognized Opeerator!");
	}
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner input = new Scanner(System.in);
		Calc test = new Calc();
		test.num1 = input.nextInt();
		test.num2 = input.nextInt();
		String s1 = input.next();
		test.operation = s1.charAt(0);
		test.calculate();
		System.out.println("The calculation result is : "+test.result);
	}

}

注释版

//Scanner input = new Scanner(System.in);
//int型数据 = input.nextInt()；
//String型字符串 = input.next();
//char型字符 先获得String字符串在用字符串的charAt(0)方法 如：char1 = s1.charAt(0);

import java.util.Scanner;

public class Calc {

	//定义两个运算数
	public int num1;
	public int num2;
	
	//定义运算结果
	public double result=0.0;
	
	//定义运算符
	public char operation;
	
	//定义方法 calculate
	public void calculate() {
		if(operation == '+')
			result=num1+num2;
		else if(operation == '-')
			result=num1-num2;
		else if(operation == '*')
			result=num1*num2;
		else if(operation == '/')
			if(num2 != 0)
				result=num1*1.0/num2;
			else
			//除数是0，输出 输入错误 的提示
				System.out.println("Incorrect input!");
		else
		//其他运算符，输出 无法识别运算符 的提示
			System.out.println("Unrecognized Opeerator!");
	}
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		//新建Scanner 对象 input
		Scanner input = new Scanner(System.in);
		Calc test = new Calc();
		System.out.println("Input two arithmetic numbers and an operator to start calculation.");
		
		//调用input的next()方法获取控制台输入 （int型数据）
		test.num1 = input.nextInt();
		test.num2 = input.nextInt();
		
		//定义一个String类型的变量s1来接收控制台输入的字符 （String型字符串）
		String s1 = input.next();

		//调取变量s1的charAt(0)方法获取第一个字符 （char型字符）
		test.operation = s1.charAt(0);
		test.calculate();
		System.out.println("The calculation result is : "+test.result);
	}

}