利用 switch...case 编写简单计算器的 Java 程序

在本文中，我们将了解如何使用 switch-case 构造一个简单的计算器。switch 语句计算一个表达式，将表达式的值与 case 子句进行匹配，并执行与该 case 关联的语句。

以下是我们要执行的算术操作。

• 加法
• 减法
• 乘法
• 除法
• 取整除
• 模

下面演示了同样的内容 −

输入

假设我们的输入是 −

The two inputs: 40.0 and 12.0
Operator:%

输出

预期的输出将是 −

The result is 40.0 % 12.0 = 4.0

算法

Step 1 - START
Step 2 - Declare three values namely my_input_1, my_input_2 and my_result and declare a character value namely operator.
Step 3 - Read the required values from the user/ define the values
Step 4 - Define case statements which takes ‘operator’ value as switch case to calculate the sum, difference, multiplication, division, modulus.
Step 5 - Pass the operator value to the case statements to calculate the arithmetic operation between the two inputs ‘my_input_1’ and ‘my_input_2’
Step 7 - Display the result
Step 8 - Stop

示例 1

在这里，输入由用户根据提示输入。您可以在我们的coding ground 工具 中实时地尝试此示例。

import java.util.Scanner;
public class OperatorSwitch {
   public static void main(String[] args) {
      char operator;
      Double my_input_1, my_input_2, my_result;
      System.out.println("Required packages have been imported");
      Scanner my_scanner = new Scanner(System.in);
      System.out.println("A reader object has been defined ");
      System.out.println("Enter the first number");
      my_input_1 = my_scanner.nextDouble();
      System.out.println("Enter the second number");
      my_input_2 = my_scanner.nextDouble();
      System.out.println("Enter any of the following operator: +, -, *, /, %");
      operator = my_scanner.next().charAt(0);
      switch (operator) {
         case '+':
            my_result = my_input_1 + my_input_2;
            System.out.println(my_input_1 + " + " + my_input_2 + " = " + my_result);
            break;
         case '-':
            my_result = my_input_1 - my_input_2;
            System.out.println(my_input_1 + " - " + my_input_2 + " = " + my_result);
            break;
         case '*':
            my_result = my_input_1 * my_input_2;
            System.out.println(my_input_1 + " * " + my_input_2 + " = " + my_result);
            break;
         case '/':
            my_result = my_input_1 / my_input_2;
            System.out.println(my_input_1 + " / " + my_input_2 + " = " + my_result);
            break;
         case '%':
            my_result = my_input_1 % my_input_2;
            System.out.println(my_input_1 + " % " + my_input_2 + " = " + my_result);
            break;
         default:
            System.out.println("The operator you have selected is invalid");
            break;
      }
   }
}

输出

Required packages have been imported
A reader object has been defined
Enter the first number
40
Enter the second number
12
Choose any of the following operator: +, -, *, /, %
%
40.0 % 12.0 = 4.0

示例 2

在这里，整数已被预先定义好，其值被访问并在控制台中显示。

public class OperatorSwitch {
   public static void main(String[] args) {
      char operator;
      Double my_input_1, my_input_2, my_result;
      my_input_1 = 40.0;
      my_input_2 = 12.0;
      operator = '%';
      System.out.println("The two numbers are defined as " +my_input_1 +" and " +my_input_2);
      System.out.println("The operator is defined as " +operator);
      switch (operator) {
         case '+':
            my_result = my_input_1 + my_input_2;
            System.out.println(my_input_1 + " + " + my_input_2 + " = " + my_result);
            break;
         case '-':
            my_result = my_input_1 - my_input_2;
            System.out.println(my_input_1 + " - " + my_input_2 + " = " + my_result);
            break;
         case '*':
            my_result = my_input_1 * my_input_2;
            System.out.println(my_input_1 + " * " + my_input_2 + " = " + my_result);
            break;
         case '/':
            my_result = my_input_1 / my_input_2;
            System.out.println(my_input_1 + " / " + my_input_2 + " = " + my_result);
            break;
         case '%':
            my_result = my_input_1 % my_input_2;
            System.out.println(my_input_1 + " % " + my_input_2 + " = " + my_result);
            break;
         default:
            System.out.println("The operator you have selected is invalid");
            break;
      }
   }
}

输出

The two numbers are defined as 40.0 and 12.0
The operator is defined as %
40.0 % 12.0 = 4.0

AmitDiwan

更新于： 2022 年 2 月 22 日

4 千 + 次浏览

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