Java输出错误

Question

我无法让它正常工作。它按预期运行，并进行数学运算，但随后循环一次，然后结束。我需要它循环直到用户决定结束它，或者只运行一次。

import java.util.Scanner;

public class java {
  public static void main(String args[]) {
    System.out.println("Welcome to the simple Calculator program");
    System.out.println("Please type what type of math you would like to do: ");
    System.out.println("1=Addition");
    System.out.println("2=Subtraction");
    System.out.println("3=Multiplication");
    System.out.println("4=Division");
    System.out.println("5=Sqrt");
    Scanner input = new Scanner(System.in);
    int math = input.nextInt();
    if (math == 1) {
      Scanner a = new Scanner(System.in);
      int a1;
      int a2;
      int asum;
      System.out.print("Please enter the first number:  ");
      a1 = a.nextInt();

      System.out.print("Please enter the second number:  ");
      a2 = a.nextInt();

      asum = a2 + a1;
      System.out.print("The sum is: " + asum + "Thank You for using this program");
    }

    Scanner number = new Scanner(System.in);
    int number1;
    int number2;
    int sum;
    System.out.print("Enter first number:  ");
    number1 = number.nextInt();

    System.out.print("Enter Second number:  ");
    number2 = number.nextInt();

    sum = number1 + number2;

    System.out.printf("Sum is %d\n", sum);
  }
}

Answer 1

使用

   do{
      // do something.
   } while(some condition);

并重复相同的扫描仪以获取输入。您还可以在菜单中再添加一个选项，以便使用 while 条件重复和评估该选项。