java - 在java中使用while循环在每次迭代中添加到不同的变量

Question

我应该知道该怎么做，但也许我只是累了。无论如何，我需要编写一个简单的 while 循环，询问用户他们想要每个项目的数量(使用扫描仪)。有四项。目前的代码如下所示:

int item1Amount;
int item2Amount;
int item3Amount;
int item4Amount;
int c = 1;
while (x != -1) {
    System.out.print("Enter the number of Item " + c + " you would like to purchase: ");
    item1Amount = input.nextInt();
    c++;
}

我在逻辑上遇到的问题是，当它返回循环时，它将要求项目 2、3 和 4，但仍将用户输入输入为 item1Amount。如何才能正确完成此操作？

Answer 1

使用 ArrayLists(最干净的版本):

ArrayList<Integer> itemAmounts = new ArrayList<Integer>();
int c = 1;
int x = 0;
while(x!=-1){
    System.out.print("Enter the number of Item "+c+" you would like to purchase: ");
    int x = input.nextInt();
    itemAmounts.add(x);
    c++;
}

使用数组(仅限四个项目)

final int NUMB_ITEMS = 4;
int[] itemAmounts = new int[NUMB_ITEMS];
int c = 0;
int x = 0;
while(x!=-1 && c < NUMB_ITEMS){
    System.out.print("Enter the number of Item "+(c+1)+" you would like to purchase: ");
    int x = input.nextInt();
    itemAmounts[c] = x;
    c++;
}

没有任何数据结构:

int item1Amount;
int item2Amount;
int item3Amount;
int item4Amount;
int c = 1;
int a = 0;
while(x!=-1 && c<= 4){
    System.out.print("Enter the number of Item "+c+" you would like to purchase: ");
    a=input.nextInt();
    switch(c){
        case 1:
            item1Amount = a;
            break;
        case 2:
            item2Amount = a;
            break;
        case 3:
            item3Amount = a;
            break;
        case 4:
            item4Amount = a;
            break;
        default:
            break;
    }
    c++;
}

没有任何数据结构，也没有开关(呃……第 4 章很糟糕):

int item1Amount;
int item2Amount;
int item3Amount;
int item4Amount;
int c = 1;
int a = 0;
while(x!=-1 && c<= 4){
    System.out.print("Enter the number of Item "+c+" you would like to purchase: ");
    a=input.nextInt();
    if(c == 1){
        item1Amount = a;
    } else if(c == 2){
        item2Amount = a;
    } else if (c == 3){
        item3Amount = a;
    } else if (c == 4) {
        item4Amount = a;
    }
    c++;
}