如何在Java中将输入值增加两倍

Question

我的程序要求个人输入2个数字（即：10和20）。 我想输出是：

连号：10 12 14 16 18 20

我的代码：

System.out.println("Enter an integer:"); 
    int firstNum = keyboard.nextInt(); 

    System.out.println("Enter another integer larger than the first one:"); 
    int secondNum = keyboard.nextInt(); 

    System.out.println(); 

    int mod = firstNum % 2; 

    while ((firstNum < secondNum) && mod == 0) 
    { 
     firstNum = firstNum + 2; 
     System.out.print("Even numbers" +firstNum); 
    } 

Answer 1

你是接近的结果你后，只需要重新安排几行的顺序并添加一个if检查。

我做了一个完整的例子，按预期运行，并允许奇数和偶数。您可以用以下代码替换您的代码：

public static void main(String[] args) 
{ 
    Scanner keyboard = new Scanner(System.in);  
    System.out.println("Enter an integer:"); 
    int firstNum = keyboard.nextInt(); 

    System.out.println("Enter another integer larger than the first one:"); 
    int secondNum = keyboard.nextInt(); 

    System.out.println(); 

    int mod = firstNum % 2; 
    //If first number is odd, increase by one to make it even. 
    if (mod != 0) 
    { 
     firstNum++; 
    } 

    System.out.print("Even Numbers: "); 
    while (firstNum <= secondNum) 
    { 
     System.out.print(firstNum + " "); 
     firstNum = firstNum + 2; 
    } 
    keyboard.close(); 
}