Initiallization Issue in Project

[B3gin3r]

Hi all,

I'm currently teaching myself C++ and have been working on a project using ncurses and vectors to create a simple maze game. I have been doing everything bit by bit, always writing a section of code, then compiling and running to see if everything is working. I've been trying to use a vector push_back which I had planned to use to create the walls of my maze and potentially replace the addch commend I used to establish the boarders. That is the point where things beak down. At this point, everything is a work in progress and there are a few variabls which have ot been used yet. The code is below and I have add a comment where the code isn't compiling.

#include <iostream>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <ncurses.h>
#include <cstdlib>

struct MazeWall{
int x,y;
MazeWall(int col, int row);
MazeWall();
};

class MazeClass{
int x,y,maxX,maxY;
char Wall;
MazeWall MazeW;
std::vector<MazeWall> Maze;

public:
MazeClass();
~MazeClass();
};


int main()
{

char Wall=219;
int col=0;
int row=0;
int i=0;
int x=0;
int y=0;
int maxX=0;
int maxY=0;
int Esc=0;

initscr();
nodelay(stdscr, true);
keypad(stdscr, true);
noecho();
curs_set(0);
getmaxyx(stdscr,maxY,maxX);

//This is the creation of the board.Size if fixed. Need to look at how I can maximize this.
while((Esc=getch())!=27){
for(i=0; i<maxX-1; i++)
{
move(0,i);
addch(Wall);
}
for(i=0; i<maxX-1; i++)
{
move(maxY-2,i);
addch(Wall);
}

for(i=0; i<maxY-1; i++)
{
move(i,0);
addch(Wall);
}
for(i=0; i<maxY-1; i++)
{
move(i,maxX-1);
addch(Wall);
}

move(maxX,maxY);
printw("Score:");

//Everything works well until I get to this part of the code. at this point I get an "error: expected initializer before ‘<’ token" Message
MazeClass MazeClass::vector<MazeWall> Maze.push_back(Wall(40, 50));

refresh();
}
return 0;
}

The error message is "75:29: error: expected initializer before ‘<’ token"

Would someone be able to help me out here a bit. I've been looking through the internet for the last 3 hours and can't figure out what I'm doing wrong.

[Peter87]

You can't put the initialization of a static member function inside a function.

You can also not use member functions such as push_back because the object has not yet been created. You need to use the constructor.

It could look something like this:

std::vector<MazeWall> MazeClass::Maze{{40, 50}};

[B3gin3r]

Thnks for the help. That seems to have corrected the issue of the initializer. I've changed the code as follows:
MazeClass
std::vector<MazeWall> MazeClass::Maze{40,50};

I was getting an error message for the double brackets, but after removing them, the error went away. Unfortunately, I'm now getting a:

"76:23: error: invalid declarator before ‘MazeClass’
std::vector<MazeWall> MazeClass::Maze{40,50};"
^
I've played arouwith the command a bit and did a bit more net research, Most f the problems I've found seem to revolve around a missing semicolon, which as far as I can tell is not the case here.

Last annoying question as well, do I understand you correctly that I will not be able to use the push_back function at all, or is it just not an option because of how I have organized the code. In the case of the latter, is there a simplefix for that, or do I need a significant rewrite of my code?
Again, thank you very much for the input.

[Peter87]

I'm sorry. I thought it looked like an attempt to initialize a static member variable but I see now that Maze is just a regular non-static member variable so you might want to ignore what I said earlier.

If Maze is a non-static member variable (as it is in your code) you need a MazeClass object in order access the Maze vector. Also note that Maze is private so you don't have direct access to it from outside the class.

MazeClass maze;
maze.Maze.push_back(Wall(40, 50)); // error,  MazeClass::Maze is private
maze.someMemberFunctionThatUsesMaze(); // OK, assuming such a function exists 

[B3gin3r]

I've tried to use your example. I've change the code for the class as follows:

class MazeClass{
public:
int x,y,maxX,maxY;
char Wall;
maze;
MazeWall MazeW;
std::vector<MazeWall> Maze;
MazeClass();
~MazeClass();

and then following that, I amended the vector code later to read
MazeClass maze;
maze.Maze.push_back(Wall(40, 50));
The initiation error is now gone, but for a reason I don't understand It has a problem with the vector and is giving me this error:

18:1: error: ‘maze’ does not name a type
maze; //This seems to be a problem in how I tried to declare maze in the class
^
81:32: error: ‘Wall’ cannot be used as a function
maze.Maze.push_back(Wall(40, 50)); // Here is a problem with the actual vecor code at the end.

I'm guessing I have declared maze incorrectly in the class, and that is causing the other problems. AM I at least on the right track?

Again thanks a lot for any help.