开关语句中的函数调用

嘿伙计们，我正在尝试弄清楚如何使用 switch 语句在我的代码中调用函数。我试图寻找许多不同的参考资料，但无论如何似乎都不起作用，如果有人能让我走上正确的道路，那将是一个很大的帮助。代码如下：

#include <iostream>
#include <string>
using namespace std;
int playGame(string word); 
int main() 
{
int choice;
bool menu = true;
do{
cout <<"Please select one of the following options:  n";
cout << "1: Playn"
    "2: Helpn"
    "3: Confign"
    "4: Quitn";
cout << "Enter your selection (1, 2 and 3): ";
cin >> choice;
//*****************************************************************************
// Switch menu to display the menu.
//*****************************************************************************
    switch (choice)
 {
      case 1:
        cout << "You have chosen playn";
        int playGame(string word); 
        break;
     case 2:
        cout << "You have chosen helpn";
        cout << "Here is a description of the game Hangman and how it is    played:nThe      word to guess is represented by a row of dashes, giving the number of letters, numbers and category. If the guessing player suggests a letter or number which occurs in the word, the other player writes it in all its correct positions";
        break; 
         case 3:
        cout << "You have chosen Quit, Goodbye.";
        break;
    default:
        cout<< "Your selection must be between 1 and 3!n";
    }
}while(choice!=3);    
getchar();
getchar();

cout << "You missed " << playGame("programming");
cout << " times to guess the word programming." << endl;
}



int playGame(string word) //returns # of misses
{
    //keep track of misses
    //guess is incorrect
    //repeated guess of same character
    //guess is correct 
    int misses = 0;
    int exposed = 0; 
    string display = word;
    for(int i=0; i< display.length(); i++)
        display[i] ='*';

    while(exposed < word.length()) {
        cout << "Miss:" << misses << ":";
        cout << "Enter a letter in word ";
        cout << display << " : ";
        char response;
        cin >> response; 
        bool goodGuess = false; 
        bool duplicate = false;
        for(int i=0 ; i<word.length() ; i++) 
            if (response == word[i]) 
            if (display[i] == word[i]) {
                cout << response << " is already in the word.n";
                duplicate = true; 
                break;
            } else {
                display[i] = word[i];
                exposed++; 
                goodGuess = true; 
            }
            if (duplicate)
                continue;
            if (!goodGuess){
                misses ++;
            cout << response << " is not in the word.n";
            }
    }
    cout << "Yes, word was " << word << "." << endl;
    return misses;
}