用户输入，一次将一个值填充到数组中JAVA [英] User input to populate an array one value at a time JAVA

问题描述

我试图弄清楚如何从用户那里获取输入并将其存储到数组中。我不能使用 arrayList （简单的方法，大声笑），而是使用标准的 array [5] 。我已经在这里和Google上进行过搜索，由于大量的问题和答复，我尚未找到好的答案。使用扫描仪获取输入不是问题。将输入存储在数组中不是问题。我遇到的麻烦是我需要一次存储一个输入。

I am trying to figure out how to take input from a user and store it into an array. I cannot use an arrayList (the easy way lol) but rather a standard array[5]. I have looked on here and on google and because of the sheer amount of questions and responses I have yet to find a good answer. Using scanner to get input is not a problem. Storing the input in an array is not the problem. What i am having trouble with is that I need to store one input at a time.

当前我正在使用for循环来收集信息，但它想收集整个信息

Currently I was using a for loop to gather information but it wants to gather the entire array at once.

    for (int i=0;i<5;i++)
                array[i] = input.nextInt();

    for (int i=0;i<array.length;i++)
                System.out.println(array[i]+" ");

我一直在搞弄它，但是如果我删除了第一个for循环，我不确定放在array []括号中。 BlueJ只是说 array []不是语句

I have been messing around with it, but if i remove the first for loop, im not sure what to put in the array[] brackets. BlueJ just says that "array[] is not a statement"

我如何一次只接受一个值，让用户确定是否要执行下一个？

How can I accept just one value at a time and let the user determine if they want to do the next?

这是一项家庭作业，但该作业是关于使用字符串命令创建控制台的，这是我需要了解以完成其余部分的概念

This is for a homework assignment, but the homework assignment is about creating a console with commands of strings and this is a concept that i need to understand to complete the rest of the project which is working fine.

推荐答案

将此用作参考实现。有关如何设计简单控制台程序的一般说明。我目前正在使用JDK 6。如果您使用的是JDK 7，则可以在字符串中使用 switch case 而不是 if-else 。

Use this as a reference implementation. General pointers on how a simple console program can be designed. I'm using JDK 6 at the moment. If you're on JDK 7 you can use switch case with strings instead of the if-else.

public class Stack {

    int[] stack; // holds our list
    int MAX_SIZE, size; /* size helps us print the current list avoiding to 
                           print zer0es & the ints deleted from the list */    
    public Stack(int i) {
        MAX_SIZE = i; // max size makes the length configurable
        stack = new int[MAX_SIZE]; // intialize the list with zer0es
    }

    public static void main(String[] args) throws IOException {
        new Stack(2).run(); // list of max length 2
    }

    private void run() {
        Scanner scanner = new Scanner(System.in);
        // enter an infinite loop
        while (true) {
            showMenu(); // show the menu/prompt after every operation

            // scan user response; expect a 2nd parameter after a space " "
            String[] resp = scanner.nextLine().split(" "); // like "add <n>"
            // split the response so that resp[0] = add|list|delete|exit etc.
            System.out.println(); // and resp[1] = <n> if provided

            // process "add <n>"; check that "<n>" is provided
            if ("add".equals(resp[0]) && resp.length == 2) {
                if (size >= MAX_SIZE) { // if the list is full
                    System.out.print("Sorry, the list is full! ");
                    printList(); // print the list
                    continue; // skip the rest and show menu again
                }
                // throws exception if not an int; handle it
                // if the list is NOT full; save resp[1] = <n>
                // as int at "stack[size]" and do "size = size + 1"
                stack[size++] = Integer.parseInt(resp[1]);
                printList(); // print the list

            // process "list"
            } else if ("list".equals(resp[0])) {
                printList(); // print the list

            // process "delete"
            } else if ("delete".equals(resp[0])) {
                if (size == 0) { // if the list is empty
                    System.out.println("List is already empty!\n");
                    continue; // skip the rest and show menu again
                }
                // if the list is NOT empty just reduce the
                size--; // size by 1 to delete the last element
                printList(); // print the list

            // process "exit"
            } else if ("exit".equals(resp[0])) {
                break; // from the loop; program ends

            // if user types anything else
            } else {
                System.out.println("Invalid command!\n");
            }
        }
    }

    private void printList() {
        System.out.print("List: {"); // print list prefix

        // print only if any ints entered by user
        if (size > 0) { // are available i.e. size > 0
            int i = 0;
            for (; i < size - 1; i++) {
                System.out.print(stack[i] + ",");
            }
            System.out.print(stack[i]);
        }
        System.out.println("}\n"); // print list suffix
    }

    private void showMenu() {
      System.out.println("Enter one of the following commands:");
      // Check String#format() docs for how "%" format specifiers work
      System.out.printf(" %-8s: %s\n", "add <n>", "to add n to the list");
      System.out.printf(" %-8s: %s\n", "delete", "to delete the last number");
      System.out.printf(" %-8s: %s\n", "list", "to list all the numbers");
      System.out.printf(" %-8s: %s\n", "exit", "to terminate the program");
      System.out.print("$ "); // acts as command prompt
    }
}

示例运行：

Enter one of the following commands:
 add <n> : to add n to the list
 delete  : to delete the last number
 list    : to list all the numbers
 exit    : to terminate the program
$ list

List: {}

Enter one of the following commands:
 add <n> : to add n to the list
 delete  : to delete the last number
 list    : to list all the numbers
 exit    : to terminate the program
$ add 1

List: {1}

Enter one of the following commands:
 add <n> : to add n to the list
 delete  : to delete the last number
 list    : to list all the numbers
 exit    : to terminate the program
$ add 2

List: {1,2}

Enter one of the following commands:
 add <n> : to add n to the list
 delete  : to delete the last number
 list    : to list all the numbers
 exit    : to terminate the program
$ add 3

Sorry, the list is full! List: {1,2}

Enter one of the following commands:
 add <n> : to add n to the list
 delete  : to delete the last number
 list    : to list all the numbers
 exit    : to terminate the program
$ delete

List: {1}

Enter one of the following commands:
 add <n> : to add n to the list
 delete  : to delete the last number
 list    : to list all the numbers
 exit    : to terminate the program
$ delete

List: {}

Enter one of the following commands:
 add <n> : to add n to the list
 delete  : to delete the last number
 list    : to list all the numbers
 exit    : to terminate the program
$ delete

List is already empty!

Enter one of the following commands:
 add <n> : to add n to the list
 delete  : to delete the last number
 list    : to list all the numbers
 exit    : to terminate the program
$ exit

（说实话：我很无聊。所以，我写了它，并认为不妨将其发布）

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