Question

我在代码中最后一次执行while循环时遇到问题。我有条件设置为在输入Y，N，y或n时停止外观，但即使输入了这些值，循环仍继续运行并继续询问Y或N.在调试中，似乎Ascii值为字符也存储在变量中？当输入这4个字符中的任何一个时，我需要更改do do loop end吗？

#include <string>
#include <iostream>
#include <iomanip>``

using namespace std;

int main()
{   
  int numberOfShapes, i, j, k, rectangleBase, rectangleHeight;
  char star = '*';
  char filled;

  do
   {
    cout << "Enter the integer between 6 and 20 that you would like to be the base of the rectangle: ";
    cin >> rectangleBase;

   }while (rectangleBase < 6 || rectangleBase > 20);

  rectangleHeight = rectangleBase / 2;
  do
   {
    cout << "Enter the number of shapes you would like to draw(Greater than 0 and less than or equal to 10: ";
    cin >> numberOfShapes;
   } while (numberOfShapes <= 0 || numberOfShapes > 10);

  do
  {
    cout << "Would you like a filled shape? [Y or N]: ";
    cin >> filled;
  } while (filled != 'Y' || filled != 'N' || filled != 'y' || filled != 'n');

Answer 1

您的循环结束条件错误：

while (filled != 'Y' || filled != 'N' || filled != 'y' || filled != 'n');

考虑价值为'y'，那么您的条件将为：

(true || true || false || true)

评估为true。

更改为：

while (filled != 'Y' && filled != 'N' && filled != 'y' && filled != 'n');

然后它将是：

-> 'y' (true && true && false && true) -> false
-> 'l' (true && true && true && true) -> true

Answer 2

您需要使用&&而不是||：

} while (filled != 'Y' && filled != 'N' && filled != 'y' && filled != 'n');

Answer 3

如果按照你的说法写下它，也许它会更清楚，并有助于避免这些错误：

do
{
    cout << "Would you like a filled shape? [Y or N]: ";
    cin >> filled;
    if (filled == 'Y' || filled == 'N' || filled == 'y' || filled == 'n')
       break;
} 
while (true);

Chars in while while循环条件

3 个答案: