Error: expected initializer before '.' token

Question

I am fairly new to using classes and the Object Oriented side of C++ and get the error in the title.

I am writing a game of Tetris using SDL.

I have a class definition in shapes.h

class shape
{
public:
    SDL_Surface *colour;
    int rotation1[4][4];
    int rotation2[4][4];
    int rotation3[4][4];
    int rotation4[4][4];

    bool load();
    void move();

    shape();
};

and in main.h i have included shapes.h and defined instances of the class with

//Create shapes
shape O, T, S, L, R, Z, I;

I also have seperate files for each shape such as I.cpp as each shape will have different code for loading the image for its colour of block onto the SDL_Surface colour and for the various arrays of different rotations of the block, so i seperated this into one file for each block.

In I.cpp I have included main.h and tried to set up the load function for I as follows:

bool I.load()
{
    //if loading the cyan square texture fails
    if ((I.colour = surface::onLoad("../Textures/cyanSquare.png")) == NULL)
    {
        //print error
        cout << "Unable to load cyanSquare.png";
        //return fail
        return false;
    }

    I.rotation1 = {{7,7,7,7},
                   {0,0,0,0},
                   {0,0,0,0},
                   {0,0,0,0}};
    I.rotation2 = {{0,0,7,0},
                   {0,0,7,0},
                   {0,0,7,0},
                   {0,0,7,0}};
    I.rotation3 = {{7,7,7,7},
                   {0,0,0,0},
                   {0,0,0,0},
                   {0,0,0,0}};
    I.rotation4 = {{0,0,7,0},
                   {0,0,7,0},
                   {0,0,7,0},
                   {0,0,7,0}};

    return true;
}

When I try to compile this (using GCC) it reports an error on line 3 of I.cpp of:

error: expected initializer before '.' token

I have absolutely no idea what this means, and could not find anything of use searching google for this error code, so any help would be appreciated.

It might be time to put down the compiler and pick up [a good book](http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list). — Robᵩ, Apr 29 '11 at 16:28

score 4 · Answer 1 · answered Apr 29 '11 at 16:24

4

This is not valid C++. I is a variable; you cannot define a member function for a specific variable (bool I.load()). Perhaps you meant bool shape::load()?

answered Apr 29 '11 at 16:24

Oliver Charlesworth

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Jay Zhu · Accepted Answer · 2011-04-29T16:30:45.177

bool I.load()

shouldn't it be bool shape::load() ?

I is just an instance of type 'shape'. How can you use 'I' inside the function implementation as it knows nothing about the 'I' instance!

You probably want to do this: 1. Add a construct with parameter to specify the picture for the instance:

class shape
{
public:
//....

    shape(const char* pImagePath);
private:
    const char* m_pImagePath;
};

and implement the constructor as:

shape::shape(const char* image_path) : m_pImagePath(pImagePath) {}

Your load() then can be implemented as:

bool shape::load()
{
    //if loading the cyan square texture fails
    if ((colour = surface::onLoad(m_pImagePath)) == NULL)
    {
        cout << "Unable to load cyanSquare.png";
        return false;
    }

    rotation1 = {{7,7,7,7},
                 {0,0,0,0},
                 {0,0,0,0},
                 {0,0,0,0}};
    rotation2 = {{0,0,7,0},
                 {0,0,7,0},
                 {0,0,7,0},
                 {0,0,7,0}};
    rotation3 = {{7,7,7,7},
                 {0,0,0,0},
                 {0,0,0,0},
                 {0,0,0,0}};
    rotation4 = {{0,0,7,0},
                 {0,0,7,0},
                 {0,0,7,0},
                 {0,0,7,0}};

    return true;
}

Create instance 'I' as following:

shape I("../Textures/cyanSquare.png");

I think that would work, is it not therefore possible to specify a different function for each instance of the class, because as you can see they will each have different arrays and a different texture. I am sorry if I sound ridiculous, i have never used classes before. — FrogInABox, Apr 29 '11 at 16:25
I have used your method, and it all appears to work fine other than creating the instance 'I' - i get two errors on this line: `expected identifier before string constant` and `expected ',' or '...' before string constant` — FrogInABox, Apr 29 '11 at 16:47

Error: expected initializer before '.' token

2 Answers2