C++ 猜谜游戏错误

Question

我不知道如何在“int main()”的括号中声明“随机”，需要帮助。 （我是 C++ 初学者）

请查看我的代码，试一试，当您认为您知道如何解决此问题时，请通知我并提供答案。这对我来说意义重大。谢谢！同时，我也会继续努力自己解决问题。

注意：如果你想具体一点，我正在使用 Code::Blocks。

错误出现在我的代码的第 7/9 行。

下面是我的更新代码：

#include <iostream>
#include <stdlib.h>
#include <conio.h>

using namespace std;

int main()
{
int rn = random() % 21; // generates a random int from 0 to 20

// First output asking the user to guess the number
cout << "Please guess my number :" << endl;
int u;
cin >> u;

while (u != rn) // Calculates the answer that you give
{

// If the user's number is greater than the random number
// the program will let you know it's too large
if (u > rn)
{
    cout << "You guessed too big!" << endl;
}
// On the other hand, if the user guesses to small
// the program will tell them that it's too small
else if (u < rn)
{
    cout << "You guessed too small!" << endl;
}

// If the user does not get the right number, the program
// will tell the user to guess again
cout << "Please guess again :" << endl;
cin >> u;

}

// If the user guesses the number correctly, the program
// will say that they got it right, and end the program
cout << "You guessed it right!" << endl;
getch();
}

这是更新后的编译器错误：

||=== 构建：在猜数字中调试（编译器：GNU GCC 编译器）===|

C:\Users\Minecraftship\Documents\CPP Programs From Book\Guess The Number\main.cpp||In function 'int main()':|

C:\Users\Minecraftship\Documents\CPP Programs From Book\Guess The Number\main.cpp|12|

错误：“随机化”未在此范围内声明|

||=== 构建失败：1 个错误，0 个警告（0 分钟，0 秒）===|

Answer 1

去掉 main 附近的分号，编译器会告诉你问题出在哪里：

int main ();

应该是

int main ()

即使在修复此问题后，您的代码也不会编译，因为您尚未声明 std 命名空间。您现在可以将此行放在顶部using namespace std;，但它是bad practice。您应该使用范围解析运算符手动声明它。

以及上面 cmets 中已经提到的许多其他问题，请务必仔细阅读编译器输出，因为它会告诉您是哪一行导致了问题。

您的代码应如下所示：

#include <iostream>
#include <stdlib.h>
#include <conio.h>

using namespace std;

int main()
{
int rn = random() % 21; // generates a random int from 0 to 20

// First output asking the user to guess the number
cout << "Please guess my number :" << endl;
int u;
cin >> u;

while (u != rn) // Calculates the answer that you give
{

    // If the user's number is greater than the random number
    // the program will let you know it's too large
    if (u > rn)
    {
        cout << "You guessed too big!" << endl;
    }
    // On the other hand, if the user guesses to small
    // the program will tell them that it's too small
    else if (u < rn)
    {
        cout << "You guessed too small!" << endl;
    }

    // If the user does not get the right number, the program
    // will tell the user to guess again
    cout << "Please guess again :" << endl;
    cin >> u;

}

// If the user guesses the number correctly, the program
// will say that they got it right, and end the program
cout << "You guessed it right!" << endl;
getch();
}

Answer 2

其他人得到了它。 main() 等方法的签名后没有分号。

还有一件事没有提到，我猜你想要

while (u != rn)

另外，请注意“=”和“==”的区别。

顺便说一句——欢迎使用 C++！！！

Answer 3

一个更便携的版本（不使用 conio.h），它可以让计算机与自己对战：

#include <iostream>
#include <cstdlib>
#include <ctime>

int get_random_in_range(int min, int max)
{
    return std::rand() % (max - min) + min;
}

// returns 0 if user guessed right, negative value if user
// guessed too small, positive if user guessed too big
int check_user_guess(int guess, int my_secret)
{
    return guess - my_secret;
}

int main ()
{
    int my_guess = get_random_in_range(1, 10);

    std::cout << "I think of " << my_guess << std::endl;

    std::cout << "Please guess my number: ";
    int user_guess = get_random_in_range(1, 10);
    std::cout << user_guess << std::endl;

    while (check_user_guess(user_guess, my_guess) != 0)
    {
        std::cout << "You guessed " << user_guess << std::endl;

        if (check_user_guess(user_guess, my_guess) > 0)
        {
            std::cout << "You guessed too big!" << std::endl;
        }
        else if (check_user_guess(user_guess, my_guess) < 0)
        {
            std::cout << "You guessed too small!" << std::endl;
        }

        std::cout << "Please guess again: ";
        user_guess = get_random_in_range(1, 10);
        std::cout << user_guess << std::endl;

    }

    std::cout << std::endl << "You guessed it right!";
}

在这里试试：http://coliru.stacked-crooked.com/a/5bf0b9201ef57529