I've tried to put AI into this code for so long it's breaking me emotionally. Please fix my void Game::play(SDL_Surface *screen) function. Please just show me anything. Help me make this program work!.

In the code X or the ai takes it turn whenever the mouse moves. I can click to create circles but an x mark will cover it as I move the cursor. The problem lies with in the Game.cpp file. I have a function called void Game::play(SDL_Surface *screen) that calls other void functions during a do while loop. Inside my check_victory function at the bottom it return 1 if nobody won the game which keeps the loop running because continuer=1.

Header file Game.h

#ifndef GAME_H_INCLUDED
#define GAME_H_INCLUDED

enum {EMPTY, CIRCLE, CROSS};
class Game
{
    public:
        Game();
        void play(SDL_Surface* screen);
        //Starts of your voids
		void get_computer_move(SDL_Surface* screen);
		void get_player_move(SDL_Surface* screen);
		void init_grid(SDL_Surface* screen);

		int check_victory(SDL_Surface* screen);
        ~Game();
		//0x004119d9

    private:
        SDL_Surface *board, *cmark, *xmark, *horizontale, *verticale, *diagonale1, *diagonale2;
        SDL_Event event;
        int grid[3][3], continuer, i, j, turn, end, nowinner, ai, ai2;
        SDL_Rect position, positionforme, positionwon, positionforai;
};


#endif // GAME_H_INCLUDED

Cpp file Game.cpp

#include <iostream>
#include <SDL.h>
#include <SDL_image.h>
#include <time.h>
#include "Game.h"


Game::Game()
{
    cmark= IMG_Load("cmark.jpg");
    xmark= IMG_Load("xmark.jpg");
    board= IMG_Load("board.jpg");
    horizontale=IMG_Load("horizontale.jpg");
    verticale=IMG_Load("verticale.jpg");
    diagonale1=IMG_Load("diagonale1.png");
    diagonale2=IMG_Load("diagonale2.png");
}


void Game::init_grid(SDL_Surface* screen)
{
	for(int i=0; i<3; i++)
    {
        for(j=0; j<3; j++)
        {
            grid[i][j]=EMPTY;
        }
    }
}
void Game::get_player_move(SDL_Surface* screen)
{	
	if (event.type == SDL_MOUSEBUTTONDOWN )
	{				
		if (grid[event.button.y/70][event.button.x/70] == EMPTY)
					
			positionforme.x=((event.button.x/70)*70)+15;
			positionforme.y=((event.button.y/70)*70)+15;
			//Afficher un rond, si cest au tour du rond
			grid[event.button.y/70][event.button.x/70]=CIRCLE;
			SDL_BlitSurface(cmark, NULL, screen, &positionforme);
			SDL_Flip(screen);
			
	}	
}

void Game::get_computer_move(SDL_Surface* screen)
{
	int ai = rand()% 211;
	int ai2 = rand()% 211;	
	positionforai.x = ((ai/70)*70)+15;
	positionforai.y = ((ai2/70)*70)+15;

		if (grid [ai/70][ai2/70] == EMPTY)
		{							
			grid[ai2/70][ai/70]=CROSS;
			SDL_BlitSurface(xmark, NULL, screen, &positionforai);
			SDL_Flip(screen);
	}
}



void Game::play(SDL_Surface *screen)
{
    int continuer=1, turn=0, end=0;
	
    position.x=0;
    position.y=0;
    SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 255, 255, 255));
    SDL_BlitSurface(board, NULL, screen, &position);
    SDL_Flip(screen);


	
	while (continuer)
	{
		continuer = EMPTY;
		init_grid(screen);


		SDL_WaitEvent(&event);
		if (event.type == SDL_QUIT) break;
		
		do	
		{		
				
				
				get_player_move(screen);
				continuer= check_victory(screen);
				if (continuer== EMPTY)break;
				get_computer_move(screen);
				continuer =check_victory(screen);
				if (continuer== EMPTY)break;
				

				
			//continuer=check_victory(screen); 
			}while (continuer == EMPTY);	
		
		}
	 }		



		
	


int Game::check_victory(SDL_Surface* screen)
{
    int nowinner=0;
     //It verifies if there is a winner
        for(i=0; i<3; i++)
        {    //horizontal Win Line
            if((grid[i][0]==CROSS && grid[i][1]==CROSS && grid[i][2]==CROSS) || (grid[i][0]==CIRCLE && grid[i][1]==CIRCLE && grid[i][2]==CIRCLE))
            {
                positionwon.x=20;
                positionwon.y=i*70+34;
                SDL_BlitSurface(horizontale, NULL, screen, &positionwon);
                SDL_Flip(screen);
                end=1;
                return 0;
            }
            //Vertical Win Line
            if((grid[0][i]==CROSS && grid[1][i]==CROSS && grid[2][i]==CROSS) || (grid[0][i]==CIRCLE && grid[1][i]==CIRCLE && grid[2][i]==CIRCLE))
            {
                positionwon.x=i*70+34;
                positionwon.y=20;
                SDL_BlitSurface(verticale, NULL, screen, &positionwon);
                SDL_Flip(screen);
                end=1;
                return 0;
            }
        }
        //Diagonal Win Line
        if((grid[0][0]==CROSS && grid[1][1]==CROSS && grid[2][2]==CROSS) || (grid[0][0]==CIRCLE && grid[1][1]==CIRCLE && grid[2][2]==CIRCLE))
        {
            positionwon.x=20;
            positionwon.y=20;
            SDL_BlitSurface(diagonale1, NULL, screen, &positionwon);
            SDL_Flip(screen);
            end=1;
            return 0;
        }
        if((grid[0][2]==CROSS && grid[1][1]==CROSS && grid[2][0]==CROSS) || (grid[0][2]==CIRCLE && grid[1][1]==CIRCLE && grid[2][0]==CIRCLE))
        {
            positionwon.x=22;
            positionwon.y=20;
            SDL_BlitSurface(diagonale2, NULL, screen, &positionwon);
            SDL_Flip(screen);
            end=1; 
            return 0;
        }
        for(i=0; i<3; i++)
        {
            for(j=0; j<3; j++)
            {
                if(grid[i][j]!=EMPTY)
                {
                    nowinner++;
                }
            }
        }
        if(nowinner==9)
        {
            end=1;
            return 0;
        }
        return 1;
}

Game::~Game()
{
    SDL_FreeSurface(horizontale);
    SDL_FreeSurface(verticale);
    SDL_FreeSurface(diagonale1);
    SDL_FreeSurface(diagonale2);
    SDL_FreeSurface(xmark);
    SDL_FreeSurface(cmark);
}

Few people would just fire up your code and fix it. Firstly, what it is meant to do? I assume it's Tic Tac Toe? Secondly, what's wrong with it? Be as specific as possible.

Problem: You only draw once at the beginning of your loop, and then you go into an (almost) endless logic loop.

You need to draw your game _inside_ your main loop.

    //You are here, drawing only once.
    SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 255, 255, 255));
    SDL_BlitSurface(board, NULL, screen, &position);
    SDL_Flip(screen);


	//Then you enter an (almost) infinite loop, never drawing again.
	while (continuer)
	{
		continuer = EMPTY;
		init_grid(screen);


		SDL_WaitEvent(&event);
		if (event.type == SDL_QUIT) break;
		
		do	
		{		
				
				
				get_player_move(screen);
				continuer= check_victory(screen);
				if (continuer== EMPTY)break;
				get_computer_move(screen);
				continuer =check_victory(screen);
				if (continuer== EMPTY)break;
				

				
			//continuer=check_victory(screen); 
			}while (continuer == EMPTY);	
		
		}
	 }

I'd definitely go through Lazyfoo's excellent SDL tutorials, if I were you.

All of the tutorials are significant, but you'll especially want to look at the additional articles: "Game Loops" and "State Machines".

In addition to what Servant of the Lord stated, it seems to me that on the player's turn you don't wait for the player's action.

I don't know about SDL and know very little C++, but with my knowledge I'd fix it this way:

void Game::play(SDL_Surface *screen)
{
    int continuer=1, turn=0, end=0;
	
    position.x=0;
    position.y=0;
    SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 255, 255, 255));
    SDL_BlitSurface(board, NULL, screen, &position);
    SDL_Flip(screen);
	
    while (continuer)
    {
	continuer = EMPTY;
	init_grid(screen);
		
	do	
	{	
                // Wait for the player's action
	        SDL_WaitEvent(&event);
	        if (event.type == SDL_QUIT)
                {
                    // Exit from game
                    continuer = EMPTY;
                    break;
                }

		get_player_move(screen);
		continuer= check_victory(screen);
		if (continuer== EMPTY)  break;

                // Draw stuff

		get_computer_move(screen);
		continuer =check_victory(screen);
		if (continuer== EMPTY)  break;

                // Draw stuff
	}
        while (continuer == EMPTY);	
		
    }
}	

//You are here, drawing only once.
    SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 255, 255, 255));
    SDL_BlitSurface(board, NULL, screen, &position);
    SDL_Flip(screen);

Nah SDL_Fillrect only make a fast fill of rectangle with the same colors. I think 255, 255, 255 is white. SDL_Blitsurface only display my jped image of the board.

1. Split up your draw calls from your game logic.

2. You're flipping buffers every time you draw something