问如何在用户每次输入数据时递增一个变量？
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Stack Overflow用户

提问于 2020-03-29 17:41:33

回答 3查看 573关注 0票数 1

我有一个程序，它会提示用户输入整数，直到他们键入一个值，以继续程序的下一步。每当用户输入一个整数时，我该如何递增一个名为count的变量呢？顺便说一下，我正在使用count++来增加计数数量，我只是不知道如何在用户输入数据时使其增加。

到目前为止的代码

//variables
        int num, count = 0, high, low;
        Scanner userInput = new Scanner(System.in);

        //loop

        do {
                    System.out.print("Enter an integer, or -99 to quit: --> ");
                    num = userInput.nextInt();


                    high = num;
                    low = num;

                    //higher or lower
                    if(count > 0 && num > high)
                    {
                       high = num; 
                    }
                    else if(count > 0 && num < low)
                    {
                        low = num;
                    }
                    else
                    {
                       System.out.println("You did not enter any numbers."); 
                    }

                } while (num != -99);

        System.out.println("Largest integer entered: " + high);
        System.out.println("Smallest integer entered: " + low);

java

variables

increment

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回答 3

Stack Overflow用户

回答已采纳

发布于 2020-03-29 17:45:33

这很简单。只需将count++放在while loop中，如下所示：

// variables
int num, count = 0, high, low;
Scanner userInput = new Scanner(System.in);

// loop
do {
   System.out.print("Enter an integer, or -99 to quit: --> ");
   num = userInput.nextInt();

   count++; // here it goes

   high = num;
   low = num;

   // higher or lower
   if(count > 0 && num > high)
   {
      high = num; 
   }
   else if(count > 0 && num < low)
   {
      low = num;
   }
   else
   {
       System.out.println("You did not enter any numbers."); 
   }

} while (num != -99);

System.out.println("Largest integer entered: " + high);
System.out.println("Smallest integer entered: " + low);

票数 1

Stack Overflow用户

发布于 2020-03-29 17:43:56

您可以将count++;放在do循环中的任何位置。

票数 1

Stack Overflow用户

发布于 2020-03-29 19:18:54

我理解你为什么要使用它，但是为什么要使用计数器呢？

下面的代码使用一种不同的技术从用户那里获取整数。它还确保提供的数字确实是一个在Integer.MIN_VALUE和Integer.MAX_VALUE范围内的整数：

Scanner userInput = new Scanner(System.in);
String ls = System.lineSeparator();

int high = 0;
int low = Integer.MAX_VALUE;
int num;
String input = "";
while(input.equals("")) {
    System.out.print("Enter an integer, (q to quit): --> ");
    input = userInput.nextLine().toLowerCase();
    if (input.equals("q")) {
        if (low == Integer.MAX_VALUE) {
            low = 0;
        }
        break;
    }
    if (!input.matches("^-?\\d+$")) {
        System.err.println("Invalid Entry (" + input + ")! "
                         + "You must supply an Integer (int) value!" + ls);
        input = "";
        continue;
    }

    boolean invalidInteger = false;
    long tmpVal=0;
    try {
        tmpVal = Long.parseLong(input);
    } catch(NumberFormatException ex) {
        invalidInteger = true;
    }
    if (invalidInteger || tmpVal < Integer.MIN_VALUE || tmpVal > Integer.MAX_VALUE) {
        System.err.println("Invalid Entry (" + input + ")! " + ls
                         + "Number too large (Minimum Allowable: " + Integer.MIN_VALUE 
                         + "  Maximum Allowable: " + Integer.MAX_VALUE + ")!" + ls
                         + "You must supply an Integer (int) value!" + ls);
        input = "";
        continue;
    }
    num = Integer.parseInt(input);
    if (num > high) {
        high = num;
    }
    if (num < low) {
        low = num;
    }
    input = "";
}
System.out.println("Largest integer entered:  " + high);
System.out.println("Smallest integer entered: " + low);