5位猜码游戏中search_array函数t参数取值及do-while循环问题

这是一个5位不重复数字的猜码游戏，每位数字范围0-9，玩家逐位输入猜测后会收到三种反馈：

• *：数字在密码中且位置正确
• +：数字在密码中但位置错误
• -：数字不在密码中

我现在遇到两个问题：

1. 调用search_array函数时，参数t应该传入什么值？
2. 第二个do-while循环无法正常工作，推测两者有关联。

作业要求不可修改给定的函数，但可以新增变量或函数，希望尽量遵循这个规则。我试过传入位数5、密码数组（但t是int类型无效），现在用i作为占位符。以下是我的代码：

#include <iostream>
using namespace std;

void game_instructions(int n);
bool contains_duplicates(int a[], int n);
bool search_array(int a[], int n, int t);

int main()
{
    //Step 1: Declare your variables and constants
    const int SIZE = 5; //this constant stores the length/size of the code
    int randcode[SIZE]; //this array stores the code generated randomly by the computer
    int guess[SIZE]; 
    const int SIZE2 = 5;
    int target[SIZE2]{ 1, 7, 4, 0, 9 };
    
    //this array stores the code inputted by the player/user
    //you may add more variables as needed

    //Step 2: Output game instructions by calling function game_instructions
    game_instructions(SIZE);

    //Step 3: Generate a random code and store it in the array randcode one digit at a time.
    //Each digit should be between 0 and 9 and should be stored as one array element
    //Recall that rand() % 10 can be used to generate a number between 0 and 9

    do
    {
        for (int i = 0; i < SIZE; i++)
        {
            randcode[i] = rand() % 10;
            cout << randcode[i];
        }

        //Step 4: Repeat step 3 if the array randcode contains duplicates
        //You must use function contains_duplicates to implement this step

    } while (contains_duplicates(randcode, SIZE));
    do
    {
        //Step 5: Ask the user for his guess and store it in the array guess.
        //Read one digit at a time, validate it to make sure it is between 0 and 9, and store it as one array element
        cout << "\nEnter your guess for the 5 digit code(one digit at a time) :\n";
        for (int g = 0; g < SIZE; g++)
        {
            cout << "Enter digit " << (g + 1) << ":";
            cin >> guess[g];

            while (guess[g] < 0 || guess[g] > 9)
            {
                cout << "Your guess must be between 0 and 9.\n";
                cout << "Please re-enter: ";
                cin >> guess[g];
            }
        }
        //Step 6: Output the array guess on a single line with a space after each element (see the sample output provided)
        for (int g = 0; g < SIZE; g++)
        {
            cout << guess[g] << " ";
        }
        cout << "\n";
        //Step 7: Compare the randomly generated code (randcode) with the user's guess (guess)
        //and display feedback for each digit as: *, + or –, as explained below:
        //For each digit in the user's guess do the following:
        // If it matches the digit from the random code (both value and position), output *
        // Otherwise, if it appears anywhere in the random code, output + (use function search_array here)
        // Otherwise, output -

        for (int i = 0; i < SIZE; i++)
        {
            
            if (guess[i] == randcode[i])
                cout << "* ";

            else if (search_array(randcode, 5, i))
            {
                
                cout << "+ ";
            }
            else
                cout << "- ";
        }

    } while (guess!= randcode);

        //Step 8: Repeat steps 5,6,7 until all digits have been guessed correctly

        //Step 9: Output congratulations message
        cout << "\nGood job! You guessed the code!";
}

void game_instructions(int n)
//This function outputs the game instructions.
//Its parameter n represents the length of the code.
{
    cout << "A random " << n << " digit code has been generated. You have to guess it. \n";
    cout << "For every digit you will receive feedback in the form of *, + or - \n";
    cout << " * means the digit is in the code and it is in the correct position.\n";
    cout << " + means the digit is in the code but it is not in the correct position.\n";
    cout << " - means the digit is not in the code.\n";
}


bool search_array(int a[], int n, int t)
//This function searches the array a (of size n) for a target value t.
//If t is found in the array the function returns true; otherwise it returns false.
{
    for (int i = 0; i < n; i++)
    {
        if (a[i] == t) return true;
    }
    return false;
}

bool contains_duplicates(int a[], int n)
//This function searches the array a (of size n) and returns true if the array contains duplicates; otherwise it returns false.
{
    for (int i = 0; i < n; i++)
    {
        //compare element a[i] with all the remaining elements from index i+1 to n
        for (int j = i + 1; j < n; j++)
        {
            if (a[i] == a[j]) return true;
        }
    }
    return false;
}

问题修复方案 #

1. 修正search_array的t参数传入值 #

search_array的作用是检查某个数字值是否存在于密码数组中，根据游戏规则，当当前猜测的数字位置不对时，需要验证这个数字本身是否在密码里。所以应该传入当前猜测的数字guess[i]，而不是循环下标i。修改后的判断代码：

else if (search_array(randcode, SIZE, guess[i]))

2. 修复do-while循环的终止条件 #

直接用guess != randcode是错误的——数组名代表的是数组首地址，这里比较的是两个数组的内存地址，永远不会相等。可以通过新增函数判断数组是否完全匹配来解决：

// 在main函数外新增这个函数（符合作业允许新增函数的规则）
bool arrays_equal(int a[], int b[], int n) {
    for (int i = 0; i < n; i++) {
        if (a[i] != b[i]) return false;
    }
    return true;
}

然后把循环条件修改为：

} while (!arrays_equal(guess, randcode, SIZE));

额外优化建议 #

生成随机数时，在main函数开头添加srand(time(0));，确保每次运行程序生成的密码都是随机的，否则每次启动生成的密码会完全一致。

内容的提问来源于stack exchange，提问作者bv1300