Snake - Part I

#include <stdlib.h>
#include <windows.h>
#include <string.h>
#include <stdio.h>
#include <stdbool.h>

#define LINES 25
#define COLS 80

#define fps 10
int score;
char canvas[LINES][COLS];
char *buffer = (char *) &canvas;

void drawCanvas()
{
    system("cls");
    puts(buffer);
    printf("SCORE: %d", score);
}
bool isValid(int _sa6r, int _3amood)
{
    if (_sa6r > LINES || _sa6r < 0 || _3amood > COLS || _sa6r < 0)
        return false;
    return true;
}
bool setElem(int _sa6r, int _3amood, char _7arf)
{
    if (isValid(_sa6r, _3amood))
    {
        canvas[_sa6r][_3amood] = _7arf;
        return true;
    }
    return false;

}
char getElem(int _sa6r, int _3amood)
{
    if (isValid(_sa6r, _3amood))
        return canvas[_sa6r][_3amood];
    return '\0';
}

enum {snake = '$', apple = 'o', box = 'X'};
int main (void)
{
    memset(buffer, ' ', sizeof canvas - 1);
    for (int i = 0; i < 100; i++)
    {
        if (!setElem(i, i, 'X')) break;
        drawCanvas();
        score += 10;
        Sleep(1000 / fps);
        setElem(i, i, ' ');
    }
    return 0;
}