snake.cpp

#include "snake.h"
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

snakepart::snakepart(int col, int row)
{
    x=col;
    y=row;
}

snakepart::snakepart()
    
{
    x=0;
    y=0;
}

snakeclass::snakeclass()
    
{
    initscr();
    nodelay(stdscr,true); //the program doesnt wait for the user to press the key
    keypad(stdscr,true); //activates the keyboard
    noecho();
    curs_set(0);
    getmaxyx(stdscr,maxheight,maxwidth);
    //init variables
    partchar='o';
    oldalchar=(char)64;
    foo='*';
    food.x=0;
    food.y=0;
    for(int i=0;i<5;i++)
        snake.push_back(snakepart(40+i,10));
    points=0;
    del=110000;
    get=false;
    direction='l';
    srand(time(NULL)); // This macro is the value of a null pointer constan
    putfood();
    for (int i=0;i<maxwidth-1;i++)
    {
        move(0,i);
        addch(oldalchar);
    }
    for (int i=0;i<maxwidth-1;i++)
    {
        move(maxheight-2,i);
        addch(oldalchar);
    }
    for(int i=0;i<maxheight-1;i++)
    {
        move(i,0);
        addch(oldalchar);
    }
        for(int i=0;i<maxheight-1;i++)
    {
        move(i,maxwidth-2);
        addch(oldalchar);
    }
    for(int i=0;i<snake.size();i++)
    {
        move(snake[i].y,snake[i].x);
        addch(partchar);
    }
    move(maxheight-1,0);
    printw("%d",points);
    move(food.y,food.x);
    addch(foo);
    refresh();
    
}

snakeclass::~snakeclass()
{
    nodelay(stdscr,false);
    getch();
    endwin();
}

void snakeclass::putfood() //randomly places food across the terminal
    
{
    while(1)
    {
        int tmpx=rand()%maxwidth+1;
        int tmpy=rand()%maxheight+1;
        for(int i=0; i<snake.size();i++)
            if(snake[i].x==tmpx && snake[i].y==tmpy)
                continue;
        if(tmpx>=maxwidth-2 || tmpy>=maxheight-3)
            continue;
        food.x=tmpx;
        food.y=tmpy;
        break;
    }
        move(food.y, food.x);
        addch(foo);
        refresh();  
    }

bool snakeclass::collision() // collision detection with the snake, box, food
    
{
    if(snake[0].x==0 || snake[0].x==maxwidth-1 || snake[0].y==0 || snake[0].y==maxheight-2)
        return true;
    
    for(int i=2;i<snake.size();i++)
        if(snake[0].x==snake[i].x && snake[i].y==snake[0].y)
            return true;
    if(snake[0].x==food.x && snake[0].y==food.y)
    {
        get=true;
        putfood();
        points+=10;
        move(maxheight-1,0); //increases the size of the snake
        printw("%d", points);
        if((points%100)==0)
            del-=10000;
    }else
        get=false;
    return false;
    
}
void snakeclass::movesnake()
{
    int tmp=getch();
    switch(tmp)// allows a variable to be tested for equality against a list of values.
    {
        case KEY_LEFT:
            if(direction!='r')
                direction='l';
            break;
        case KEY_UP:
            if(direction!='d')
                direction='u';
            break;
        case KEY_DOWN:
            if(direction!='u')
                direction='d';
            break;
        case KEY_RIGHT:
            if(direction!='l')
                direction='r';
            break;
        case KEY_BACKSPACE:
            direction='q';
            break;
   }
   if(!get)
   {
       move(snake[snake.size()-1].y, snake[snake.size()-1].x);
       addch(' ');
       refresh();
       snake.pop_back(); //Removes the last element in the vector, effectively reducing the container size by one.
   }

    if(direction=='l')
    {
        snake.insert(snake.begin(),snakepart(snake[0].x-1, snake[0].y));
    }
    else if(direction=='r')
    {
        snake.insert(snake.begin(),snakepart(snake[0].x+1, snake[0].y));
    }
    else if(direction=='u')
    {
        snake.insert(snake.begin(),snakepart(snake[0].x, snake[0].y-1));
    }
    else if(direction=='d')
    {
        snake.insert(snake.begin(),snakepart(snake[0].x, snake[0].y+1));
    }
    move(snake[0].y,snake[0].x);
    addch(partchar);
    refresh();
}
    
void snakeclass::start()
{
	while(1)
	{
		if(collision())
		{
			move(12,36);
			printw("Game Over");
			break;
		}
		movesnake();
		if(direction=='q')				//exit
			break;
        usleep(del); //function suspends execution of the calling thread
	}
}