将 3 个用户输入的数字相加

Question

我正在一个网站上做练习，我试图将用户输入的 3 个数字相加，仅使用三个变量。他们让你开始的代码是：

Scanner reader = new Scanner(System.in);
int sum = 0;
int read;

// WRITE YOUR PROGRAM HERE
// USE ONLY THE VARIABLES sum, reader AND read!

System.out.println("Sum: " + sum);

我正在考虑使用 for 循环，但我一直卡住了，因为我只能使用三个变量。 reader 已被扫描程序使用。 sum 将改变值，而 read 将是一个临时值。

我会用

System.out.println("Enter a number: ");
int read = Integer.parseInt(reader.nextLine());

但那只能容纳 1 个数字。任何帮助我已经坚持了一段时间。

Answer 1

这应该满足要求：

for(read = 3; read > 0; read--) {
    System.out.println("Enter a number: ");
    sum += Integer.parseInt(reader.nextLine());
}

Answer 2

这样可以吗？它显然不能扩展到数百个数字：

int read;
System.out.println("Enter a number: ");
read = Integer.parseInt(reader.nextLine());
sum += read;

System.out.println("Enter a second number: ");
read = Integer.parseInt(reader.nextLine());
sum += read;

System.out.println("Enter a third number: ");
read = Integer.parseInt(reader.nextLine());
sum += read;

No this is what i had as well, but it didn't work

完整版 - 这对我有用。

import java.util.Scanner;

public class HelloWorld {
    public static void main(String[] args) {
    Scanner reader = new Scanner(System.in);
    int sum = 0;
    int read;

    System.out.println("Enter a number: ");
    read = Integer.parseInt(reader.nextLine());
    sum += read;

    System.out.println("Enter a second number: ");
    read = Integer.parseInt(reader.nextLine());
    sum += read;

    System.out.println("Enter a third number: ");
    read = Integer.parseInt(reader.nextLine());
    sum += read;

    System.out.println("Sum: " + sum);

    }
}

输出：

Enter a number: 
22
Enter a second number: 
10
Enter a third number: 
50
Sum: 82

当然，基于 jheimbouch 所做的更简单的版本会更好：

import java.util.Scanner;

public class HelloWorld 
  {
    public static void main(String[] args) 
    {
    Scanner reader = new Scanner(System.in);
    int sum = 0;

    for(int read = 1; read <= 3; read++) 
      {
      System.out.println("Enter number " + read + ": ");
      sum += Integer.parseInt(reader.nextLine());
      }

    System.out.println("Sum: " + sum);

    }
 }

将 3 个用户输入的数字相加

Adding 3 User Input Numbers together

java

user-input

sum