Java For 循环中的多个扫描器输入
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原文地址: http://stackoverflow.com/questions/19069091/
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Multiple Scanner Input In For Loop
提问by Verdant Drift
I've just begun to learn how to program with Java and I had a question with regard to the scanner input. I'm building a little program that simply asks the user for input to create a numerical array. I was wondering if there was a way to check for the numerical input encompassing the for loop, instead of putting a while check on each of my cases in the for loop.
我刚刚开始学习如何用 Java 编程，我有一个关于扫描仪输入的问题。我正在构建一个小程序，它只是要求用户输入以创建数字数组。我想知道是否有一种方法可以检查包含 for 循环的数字输入，而不是在 for 循环中对我的每个案例进行 while 检查。
As well, any other comments or suggestions on my code to help me improve and understand what I am doing would be greatly appreciated!
同样，对我的代码有任何其他意见或建议，以帮助我改进和理解我在做什么，将不胜感激！
Thank you!
谢谢！
Edit: I'm calling this class from a 'Main' class where I run the program.
编辑：我从运行程序的“主”类调用这个类。
import java.util.Scanner; //Import the use of the Java Scanner
public class ArrayBuild { // Open Application
private static Scanner input;
public Double[] anArray;
public static int arrayCount = 0;
public ArrayBuild() { // Constructor for ArrayBuild object
input = new Scanner(System.in);
arrayCount++;
System.out.println("This will be Array: " + arrayCount);
// Array Size Declaration
System.out.println("Enter Array Size: ");
while (!input.hasNextInt()) {
System.out.println("Please enter an integer for Array size!");
input.next();
}
int n = input.nextInt();
anArray = new Double[n]; // Create 'anArray' of size n
//
for (int i = 0; i < n; i++) { // Begin For Loop
if (i == 0) {
System.out.println("Enter First Number: ");
while (!input.hasNextDouble()) {
System.out.println("Please enter a number for array data!");
input.next();
}
Double D = input.nextDouble();
anArray[i] = D;
}
else if (i > 0 && i < (n - 1)) {
System.out.println("Enter Next Number: \n");
while (!input.hasNextDouble()) {
System.out.println("Please enter a number for array data!");
input.next();
}
Double D = input.nextDouble();
anArray[i] = D;
}
else if (i == (n - 1)) {
System.out.println("Enter Final Number: ");
while (!input.hasNextDouble()) {
System.out.println("Please enter a number for array data!");
input.next();
}
Double D = input.nextDouble();
anArray[i] = D;
}
} // End For Loop
}
} // Close Class
采纳答案by hrv
One thing you can do to simplify and write clean code is to always separate the repeating code. In your case, inside the for loop, you are only changing the print statement inside the if condition. Take the other code outside like this--
为了简化和编写干净的代码，您可以做的一件事是始终将重复代码分开。在您的情况下，在 for 循环内，您只更改 if 条件内的打印语句。像这样把其他代码放在外面——
for (int i = 0; i < n; i++) { // Begin For Loop
if (i == 0)
System.out.println("Enter First Number: ");
else if (i > 0 && i < (n - 1))
System.out.println("Enter Next Number: \n");
else if (i == (n - 1))
System.out.println("Enter Final Number: ");
while (!input.hasNextDouble()) {
System.out.println("Please enter a number for array data!");
input.next();
}
Double D = input.nextDouble();
anArray[i] = D;
} // End For Loop
