Program in C to make Snake Game

/*****<soeasyprograms.blogspot.in>*****/ 
#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

/* prototypes */

void draw_line(int col, int row);

void show_score();

void add_segment();

void setup_level();



/* constants */

const int maxrow=15, maxcol=77;

const int 

snake_start_col=33,snake_start_row=7;

const char up_key='a', down_key='z', 

left_key='o', right_key='p';

const int pause_length=500000;



/* global variables */

int score, snake_length, speed, 

obstacles, level, firstpress, 

high_score=0;

char screen_grid[maxrow][maxcol];

char direction = right_key;

struct snake_segment {

  int row,col;

} snake[100];

void main()
{



  /* Variable declarations within 

main() only */

  char keypress;



  do /* restart game loop */
  {

    obstacles=4; level=1; score=0; 

speed=14;



    randomize(); /* Ensure random seed 

initiated */



    setup_level();



    /* main loop */

    do
    {

      for (int 

i=0;i<(speed*pause_length);i++) int 

j=1+i; /*pause*/



      /* If key has been hit, then 

check it is a direction key - if so,

         change direction */

      if (kbhit())
      {

        keypress=(char)getch();

        

if((keypress==right_key)||(keypress==l

eft_key)||

           

(keypress==up_key)||(keypress==down_ke

y))

          direction = keypress;

      }



      /* Add a segment to the end of 

the snake */

      add_segment();



      /* Blank last segment of snake 

*/

      

gotoxy(snake[0].col,snake[0].row);

      cprintf(" ");

      /* ... and remove it from the 

array */

        for (int 

i=1;i<=snake_length;i++)

          snake[i-1]=snake[i];

      /* Display snake in yellow */

      textcolor(YELLOW);

      for (int 

i=0;i<=snake_length;i++)
      {

        

gotoxy(snake[i].col,snake[i].row);

        cprintf("O");

      }

      /* keeps cursor flashing in one 

place instead of following snake */

      gotoxy(1,1);



      /* If first press on each level, 

pause until a key is pressed */

      if (firstpress) { 

while(!kbhit()); firstpress = 0; }



      /* Collision detection - walls 

(bad!) */

      if 

((snake[snake_length-1].row>maxrow+1)|

|(snake[snake_length-1].row<=1)||

          

(snake[snake_length-1].col>maxcol+1)||

(snake[snake_length-1].col<=1)||

      /* Collision detection - 

obstacles (bad!) */

          

(screen_grid[snake[snake_length-1].row

-2][snake[snake_length-1].col-2]=='x')

)

        keypress='x'; /* i.e. exit 

loop - game over */

      /* Collision detection - snake 

(bad!) */

      for (int 

i=0;i<snake_length-1;i++)

        if ( 

(snake[snake_length-1].row)==(snake[i]

.row) &&

             

(snake[snake_length-1].col)==(snake[i]

.col))

        {

          keypress='x'; /* i.e. exit 

loop - game over */

          break; /* no need to check 

any more segments */

        }

      /* Collision detection - food 

(good!) */

      if 

(screen_grid[snake[snake_length-1].row

-2][snake[snake_length-1].col-2]=='.')
      {

        /* increase score and length 

of snake */

        score+=snake_length*obstacles; 

show_score(); snake_length++; 

add_segment();

        /* if length of snake reaches 

certain size, onto next level */

        if (snake_length==(level+3)*2)
        {

          score+=level*1000; 

obstacles+=2; level++;  /* add to 

obstacles */

          if ((level%5==0)&&(speed>1)) 

speed--; /* increase speed every 5 

levels */

          setup_level(); /* display 

next level */

        }

      }

    } while (keypress!='x');



    /* game over message */

    if (score > high_score) high_score 

= score;

    show_score();

    gotoxy(30,6); textcolor(LIGHTRED); 

cprintf("G A M E   O V E R");

    gotoxy(30,9); textcolor(YELLOW); 

cprintf("Another Game (y/n)? ");

    do keypress=getch(); 

while((keypress!='y')&&(keypress!='n')

);



  } while (keypress=='y');

}



void setup_level()
{



 /* variables local to setup_level() 

*/

 int row,col;



  /* Set up global variables for new 

level */

  snake_length=level+4; direction = 

right_key;

  firstpress = 1;

 /* Fill grid with blanks */

  for(row=0;row<maxrow;row++)

    for(col=0;col<maxcol;col++)

     screen_grid[row][col]= ' ';



  /* Fill grid with Xs and food */

  for(int i=0;i<obstacles*2;i++)
  {

   row= rand()%maxrow;

   col= rand()%maxcol;

   if(i<obstacles)

     screen_grid[row][col]='x';

   else

     screen_grid[row][col]='.';

  }



  /* Create snake array of length 

snake_length */

  for(int i=0;i<snake_length;i++)
  {

    snake[i].row=snake_start_row;

    snake[i].col=snake_start_col+i;

  }



  /* Draw playing board */

  draw_line(1,1);

  for(row=0;row<maxrow;row++)
  {

    gotoxy(1,row+2);

    textcolor(LIGHTBLUE); 

cprintf("|");

    textcolor(WHITE);

    for(col=0;col<maxcol;col++)

      

cprintf("%c",screen_grid[row][col]);

    textcolor(LIGHTBLUE);

    cprintf("|");

  }

  draw_line(1,maxrow+2);



  show_score();

  gotoxy(2,maxrow+5);

  textcolor(LIGHTRED);

  cprintf("~~ SNAKE GAME~~ Left: %c, 

Right: %c, Up: %c, Down: %c, Exit: x. 

Any key to start.",

          

left_key,right_key,up_key,down_key);

}



void draw_line(int col, int row)
{

  gotoxy(col,row); 

textcolor(LIGHTBLUE);

  for (int col=0;col<maxcol+2;col++) 

cprintf("=");

}



void show_score()
{

  textcolor(LIGHTCYAN);

  gotoxy(2,maxrow+3);

  cprintf("Level: %05d",level);

  gotoxy(40,maxrow+3);

  textcolor(LIGHTGREEN);

  cprintf("Score: %05d",score);

  gotoxy(60,maxrow+3);

  textcolor(LIGHTMAGENTA);

  cprintf("High Score: 

%05d",high_score);

}

void add_segment()
{

  switch(direction)
  {

    case(right_key): 

snake[snake_length].row=snake[snake_le

ngth-1].row;

                     

snake[snake_length].col=snake[snake_le

ngth-1].col+1;

                     break;

    case(left_key) : 

snake[snake_length].row=snake[snake_le

ngth-1].row;

                     

snake[snake_length].col=snake[snake_le

ngth-1].col-1;

                     break;

    case(up_key)   : 

snake[snake_length].row=snake[snake_le

ngth-1].row-1;

                     

snake[snake_length].col=snake[snake_le

ngth-1].col;

                     break;

    case(down_key) : 

snake[snake_length].row=snake[snake_le

ngth-1].row+1;

                     

snake[snake_length].col=snake[snake_le

ngth-1].col;

  }

}

Game Look: