Question

以下是我必须做的事情：

“写一段从键盘读取整数序列的代码，直到用户输入一个负数。然后输出偶数整数和读取的奇数整数（不包括最终数）记住 - 0是偶数。例如，如果序列是：
2
7
15
5
88
1243
104
-1
那么输出应该是
Number of even integers: 3
Number of odd integers: 4

我的代码在输入-1后仍然继续运行。我有一种感觉，我错过了{某处或写错了代码。这是我的代码：

int oddCount = 0, evenCount = 0;
Scanner in = new Scanner(System.in);
while (oddCount>=0&&evenCount>=0){
        System.out.print("Enter an integer: ");
        int temp = in.nextInt();
        if (temp>0) {
            if (temp%2==0)
                evenCount = evenCount + 1;
            else oddCount = oddCount + 1;
            while (temp>0);
        System.out.println("Number of even integers: "+evenCount);
        System.out.println("Number of odd integers: " +oddCount);
        }
    }

Answer 1

这里有一些问题。

首先，由于您永不减少oddCount和evenCount，因此条件oddCount>=0&&evenCount>=0始终为true。

其次，你有一个无限循环的空循环，因为它的条件是true并且它没有正文：while (temp>0);

我只是取出第一个循环，这是多余的，并使用do while循环：

int oddCount = 0;
int evenCount = 0;
Scanner in = new Scanner(System.in);
do {
    System.out.print("Enter an integer: ");
    int temp = in.nextInt();
    if (temp > 0) {
        if (temp % 2==0) {
            evenCount++;
        } else {
            oddCount++;
        }
     }
 } while (temp > 0);

 System.out.println("Number of even integers: " + evenCount);
 System.out.println("Number of odd integers: "  + oddCount);

Answer 2

您的循环将始终继续，因为while (oddCount>=0&&evenCount>=0)在您的情况下始终为真。试试这样：

int oddCount = 0, evenCount = 0;
Scanner in = new Scanner(System.in);
boolean continue = true;
while (continue){
        System.out.print("Enter an integer: ");
        int temp = in.nextInt();
        if (temp>0) {
            if (temp%2==0)
                evenCount++;
            else 
                oddCount++;
        }
        else {
            System.out.println("Number of even integers: "+evenCount);
            System.out.println("Number of odd integers: " +oddCount);
            continue = false;
        }
    }

Answer 3

我认为使用do while循环也会阻止你的观察，

int oddCount = 0;
int evenCount = 0;
Scanner in = new Scanner(System.in);
do {
    System.out.print("Enter an integer: ");
    int temp = in.nextInt();
    if (temp > 0) {
        (temp % 2==0)? evenCount++:oddCount++;
    }
 } while (temp > 0);

Answer 4

您的代码只读取一个整数，然后停留在此行：while (temp>0);

以下代码解决了您的问题：

int oddCount = 0, evenCount = 0, temp;
Scanner in = new Scanner(System.in);
System.out.print("Enter an integer: ");
while (true) {
    temp = in.nextInt();
    if (temp < 0) {
        break;
    } else if (temp % 2 == 0) {
        evenCount = evenCount + 1;
    } else {
        oddCount = oddCount + 1;
    }
}
System.out.println("Number of even integers: " + evenCount);
System.out.println("Number of odd integers: " + oddCount);

Answer 5

试试这个..

Scanner s=new Scanner(System.in);
int evenCount=0, oddCount=0;
while(true)
{
System.out.println("Enter a number");
int n=s.nextInt();
   if(n<0) break;
   if(n%2==0) evenCount+=n;
   else oddCount+=n;
}
System.out.println("even count "+evenCount);
System.out.println("odd count "+oddCount);

计算偶数和奇数整数，直到遇到0

5 个答案: