For循环技巧

Question

我编写此代码是为了提示用户输入不是 5 的数字，否则游戏结束。如果用户输入一个数字 10 次，它应该会显示中奖信息。但是，如果用户输入 5，我发现自己在不显示获胜消息方面很挣扎。当用户输入 5 而不是两者时，我该怎么做才能只打印失败消息？另外，有没有办法让我的代码更简单？

for (int i = 0; i < 10; i++)
{
    cout << i+1 << "- enter a number: ";
    cin >> number;

    if (number == 5)
    { cout << "you were not supposed to enter 5!\n"; // Failure message
      break;
    }
}

cout << "Wow, you're more patient than I am, you win.\n"; // winner message

Answer 1

一种方法是扩大i 的范围并检查：

int i = 0;
for (; i < 10; i++)
{
    cout << i+1 << "- enter a number: ";
    cin >> number;

    if (number == 5)
    {
      cout << "You were not supposed to enter 5!\n"; // Failure message
      break;
    }
}

if (i == 10)
{
    cout << "Wow, you're more patient than I am, you win.\n"; // winner message
}

另一个是使用布尔标志：

bool win = true;
for (int i = 0; i < 10; i++)
{
    cout << i+1 << "- enter a number: ";
    cin >> number;

    if (number == 5)
    {
        cout << "You were not supposed to enter 5!\n"; // Failure message
        win = false;
        break;
    }
}

if (win)
{
    cout << "Wow, you're more patient than I am, you win.\n"; // winner message
}

Answer 2

循环结束的原因有两个：用户输入了 10 个非 5，或者他们输入了 5 打破了循环。所以只要查看循环后number的值是什么就可以区分两者了。

Answer 3

您可以将整个for 循环放在一个返回布尔值/整数的函数中 然后在if中调用函数

喜欢：

if(game()==true)
   cout << "Wow, you're more patient then I am, you win.\n"; // winner message
else
   cout << "you were not supposed to enter 5!\n";  // Failure message

把东西放在一个函数中是功课:)

提示：用函数内部的 return 替换 couts ;)

Answer 4

您需要使用标志，一种可能的解决方案是（这也使您的代码更简单）：

bool win = true;
for (int i = 0; i < 10 && win; i++)
{
    cout << i+1 << "- enter a number: ";
    cin >> number;

    win = number != 5;
}
if( win ) 
    cout << "Wow, you're more patient then I am, you win.\n"; // winner message
else
    cout << "you were not supposed to enter 5!\n"; // Failure message

Answer 5

一个简单的布尔标志将解决您的问题。

bool enteredFive = false;
for (int i = 0; i < 10; i++)
{
    cout << i + 1 << "- enter a number: ";
    cin >> number;

    if (number == 5)
    {
        cout << "You were not supposed to enter 5!" << endl;
        enteredFive = true;
        break;
    }
}

if (!enteredFive)
    cout << "Wow, you're more patient then I am, you win!" << endl;

Answer 6

使用标志变量 [Here isFive] 检查用户是否输入过 5 并根据该决定打印。

bool isFive = false;
for (int i = 0; i < 10; i++)
{
    cout << i+1 << "- enter a number: ";
    cin >> number;

    if (number == 5)
    { 
      isFive = true;
      cout << "you were not supposed to enter 5!\n"; // Failure message
      break;
    }
}
if(!isFive)
   cout << "Wow, you're more patient then I am, you win.\n"; // winner message

Answer 7

int number;
for (int i = 0; i < 10; i++)
{

    std::cout << i + 1 << "- enter a number: ";
    std::cin >> number;

    if (number == 5)
    {
        std::cout << "you were not supposed to enter 5!\n"; // Failure message
        return 0;
    }
    
    
}
std::cout << "Wow, you're more patient than I am, you win.\n"; // winner message