可以在没有用户输入的情况下跳过 getline() 吗？ [复制]

Question

编辑

问题是我在程序的另一点使用了cin >>，因此流缓冲区中有一个尾随换行符。

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所以主要的问题是关于 getline()，但为了更深入地了解它，您必须先查看我的代码。出于某种奇怪的原因，当我运行我的程序时，它第一次完美地运行了循环。然而第二次它跳过了我的getline(cin, inputMenu) 声明。是的，我知道这是一个非常非常基本的程序，而且我知道它没有其他错误，因为我已经测试了它的所有其他方面。 getline() 有什么我不知道的吗？

while (1)
   {
      // Reset the input each loop
      inputMenu = "ABC";

      // Menu
      cout << "Menu\n  P (Purchase)\n  S (Shut down)" << "\n\n  You decide: ";

      /* I put this if statement as a test, to make sure that it always runs getline.
         But for some odd reason when I run it I get this (see run below)*/
      if(1)
      getline(cin, inputMenu);

      //Blah blah all the other stuff if they enter a P or S. (Not an infinite  loop)

         cout << "\nYou just earned " << inputYogurt << " stamps!"
            << " Bringing your grand total to " << numStamps << "!\n" << endl;
      }
   }


---------------------- Run --------------------
Menu
  P (Purchase)
  S (Shut down)

  You decide: p

How many yogurts would you like to buy? 3

You just earned 3 stamps! Bringing your grand total to 3!


Menu
  P (Purchase)
  S (Shut down)

  You decide: Menu     <<<<<<<<<<<<<<<<<<<<<<<<<< Thats my error
  P (Purchase)
  S (Shut down)

  You decide:

-------------------------------------------------------

它跳过 getline() 语句并再次运行循环。也许我不太了解 getline() ，因为显然这似乎是问题所在。我以为当你使用getline时，它必须等待用户输入，我错了吗？

Answer 1

有时会发生。唯一的处理方法是在cin.getline() 之前调用cin.get()。还有另一种方法可以在cin.getline() 之前调用cin.flush()，但它可能不起作用。

while (1)
   {
      // Reset the input each loop
      inputMenu = "ABC";

      // Menu
      cout << "Menu\n  P (Purchase)\n  S (Shut down)" << "\n\n  You decide: ";

      /* I put this if statement as a test, to make sure that it always runs getline.
         But for some odd reason when I run it I get this (see run below)*/


      cin.get(); // add extra input
      getline(cin, inputMenu);

      //Blah blah all the other stuff if they enter a P or S.

         cout << "\nYou just earned " << inputYogurt << " stamps!"
            << " Bringing your grand total to " << numStamps << "!\n" << endl;
      }
   }

或尝试使用

cin.ignore(1000, '\n');

getline(cin, inputMenu);