我有一个叫做"迷宫.txt"的文本文件 看起来是这样的:

###############
Sacbifnsdfweovw
###############

I want to check whether the letter on the left one down from the top is S , and then to check whether the one to the right of that is an alphabetical character. Then, I ll keep checking whether the characters that follow the previous letter are alphabetical characters. These letters are to be stored in my vector path . Finally, I ll print to screen each of the alphabetical letters we ve been through. But for some reason, for that chunk of letters above, the screen only prints out S and a , and none of the others. What s wrong? Here is my code:

int main()
{
    ifstream file("maze.txt");
    if (file) {
        vector<char> vec(istreambuf_iterator<char>(file), (istreambuf_iterator<char>())); // Imports characters from file
        vector<char> path;                      // Declares path as the vector storing the characters from the file
        int x = 17;                             // Declaring x as 17 so I can use it with recursion below
        char entrance = vec.at(16);             //  S , the entrance to the maze
        char firstsquare = vec.at(x);           // For the first walkable square next to the entrance

        // Check that the entrance really has  S 
        if (entrance ==  S )                    
        { 
            path.push_back(entrance);           // Store  S  into vector  path 
        }

        // Check if the first path is an alphabetical character and thus walkable
        if (isalpha(firstsquare))               
        {
            path.push_back(firstsquare);        // Store that character into vector  path 
            isalpha(vec.at(x++));               // Recurse  isalpha  to the next adajcent square of the maze;
        }                                       // checking next character

        cout << "Path is: ";                    // Printing to screen the first part of our statement

        // This loop to print to the screen all the contents of the vector  path .
        for(vector<char>::const_iterator i = path.begin(); i != path.end(); ++i)  // 
        {
        std::cout << *i <<    ;
        }

        cout << endl;
        system ("pause");                       // Keeps the black box that pops up, open, so we can see results.
        return 0;
        }
}

顺便说一句,我是C++的新人