Snake.cpp

#include <iostream>
#include <conio.h>
#include <stdlib.h>

// Map dimensions
const int MAP_WIDTH  = 20;
const int MAP_LENGTH = 40;
const int MAP_SIZE = MAP_WIDTH * MAP_LENGTH;

// Map array
int Map[MAP_SIZE];

// The snake length
int bodyLength = 3;
// Score
int score = 0;
// Initial 0.3 second for sleep
int sec = 300;
// Determine if game is running
bool running = true;

// Returns graphical character for display from map value
char getMapValue(int value)
{

    switch (value) {
        // Return vertical wall
    case -1: return '|';
        // Return honrizontal wall
    case -2: return '-';    
        // Return food
    case -3: return 'X';

}


// Print the map
void printMap()
{
    for (int x = 0; x < MAP_WIDTH; ++x) {
        for (int y = 0; y < MAP_LENGTH; ++y) {
            // Prints the value at current x,y location
            std::cout << getMapValue(Map[x + y * MAP_WIDTH]);
        }
        // Newline
        std::cout << std::endl;
    }
}

// Initialize the map and snake position
void initialMap()
{
    // Places the initial head location in middle of map
    headxpos = MAP_WIDTH  / 2;
    headypos = MAP_LENGTH / 2;
    Map[headxpos + headypos * MAP_WIDTH] = 1;

    // Places left and right walls 
    for (int x = 0; x < MAP_WIDTH; ++x) {
        Map[x] = -1;
        Map[x + (MAP_LENGTH - 1) * MAP_WIDTH] = -1;
    }

    // Places top and bottom walls
    for (int y = 0; y < MAP_LENGTH; y++) {
        Map[0 + y * MAP_WIDTH] = -2;
        Map[(MAP_WIDTH - 1) + y * MAP_WIDTH] = -2;
    }

    // Generates first food
    generateFood();
}

// Make food
void generateFood()
{
    int xFood = 0;
    int yFood = 0;
    srand (time(NULL));//Truly random
    do {
    	
        // Generate random x and y values within the map
        xFood = rand() % (MAP_WIDTH - 2) + 1;
        yFood = rand() % (MAP_LENGTH - 2) + 1;

        // If location is not free try again
    } while (Map[xFood + yFood * MAP_WIDTH] != 0);

    // Place new food
    Map[xFood + yFood * MAP_WIDTH] = -3;
}

// Change direction from user input
void changeDirection(char key)
{

    switch (key) {
    case 'w': case 'W':
        if (direction != 1) direction = 0;
        break;
    case 's': case 'S':
        if (direction != 0) direction = 1;
        break;
    case 'd': case 'D':
        if (direction != 3) direction = 2;
        break;
    case 'a': case 'A':
        if (direction != 2) direction = 3;
        break;
    }
}

// Update the map after each move
void update(int n)
{
    // Move in direction indicated
    switch (direction) {
    case 0: move(-1, 0, n);
        break;
    case 1: move( 1, 0, n);
        break;
    case 2: move( 0, 1, n);
        break;
    case 3: move( 0,-1, n);
        break;
    }

    // Reduce snake values on map by 1
    for (int i = 0; i < MAP_SIZE; i++) {
        if (Map[i] > 0) Map[i]--;
    }
}


// Clear screen to continue
void clearScreen()
{
    // Clear the screen
    system("cls");
}

//main function printMap then clearMap loop
void run()
{
    
    initialMap();
    // While not hitting
    while (running) {
        // If a key is pressed
        if (kbhit()) {
            // Change to direction determined by key pressed
            changeDirection(getch());
        }
        // Upate the map
        update(n);

        // Clear the screen
        clearScreen();
        //clrscr();

        // Print the map
        printMap();

        // wait
        Sleep(sec);
    }

    gameOver();
}

int main()
{
    run();
    
    return 0;
}