字符在循环条件下执行

Chars in do while loop conditions

本文关键字：执行 条件下 循环 字符      更新时间：2023-10-16

我在代码中循环时遇到了问题。我设置了条件以在输入 Y、N、y 或 n 时停止查找，但即使输入了这些值，循环也会继续运行并继续请求 Y 或 N。在调试中，字符的 Ascii 值似乎也存储在变量中？当输入这 4 个字符中的任何一个时，我需要更改什么才能让 do while 循环结束？

#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');

您的循环结束条件是错误的：

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

考虑到该值是'y'则您的条件将是：

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

其计算结果为 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

你需要使用&&而不是||：

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

如果你按照你说的写它，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);
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