在本程序中，我们正在制作一个简单的计算器，根据用户输入执行加法，减法，乘法和除法。程序获取两个数字的值（由用户输入），然后要求用户输入操作（+，-，*和/），根据输入程序使用对输入的数字执行所选操作switch-case。
示例：使用的switch case编写计算器的程序
import java.util.Scanner;public class JavaExample { public static void main(String[] args) { double num1, num2; Scanner scanner = new Scanner(System.in); System.out.print("Enter first number:"); /* We are using data type double so that user * can enter integer as well as floating point * value */ num1 = scanner.nextDouble(); System.out.print("Enter second number:"); num2 = scanner.nextDouble(); System.out.print("Enter an operator (+, -, *, /): "); char operator = scanner.next().charAt(0); scanner.close(); double output; switch(operator) { case '+': output = num1 + num2; break; case '-': output = num1 - num2; break; case '*': output = num1 * num2; break; case '/': output = num1 / num2; break; /* If user enters any other operator or char apart from * +, -, * and /, then display an error message to user * */ default: System.out.printf("You have entered wrong operator"); return; } System.out.println(num1+" "+operator+" "+num2+": "+output); }}
输出：
Enter first number:40Enter second number:4Enter an operator (+, -, *, /): /40.0 / 4.0: 10.0
