Snake game in C

Question

Here is a very basic Snake game in C, which I just want to make better. The game is working perfectly but it is very annoying because when playing it, it is always blinking. I hope that somebody could try it in their compiler to see how annoying it is. How can I improve this?

Here is a screen shot of the game:

Of course it works, but I just need some advice about the design.

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <conio.h>
#include<time.h>
#include<ctype.h>
#include <time.h>
#include <windows.h>
#include <process.h>
#include <unistd.h>

#define UP 72
#define DOWN 80
#define LEFT 75
#define RIGHT 77

int length;
int bend_no;
int len;
char key;
void record();
void load();
int life;
void Delay(long double);
void Move();
void Food();
int Score();
void Print();
void gotoxy(int x, int y);
void GotoXY(int x,int y);
void Bend();
void Boarder();
void Down();
void Left();
void Up();
void Right();
void ExitGame();
int Scoreonly();

struct coordinate{
    int x;
    int y;
    int direction;
};

typedef struct coordinate coordinate;

coordinate head, bend[500],food,body[30];

int main()
{

    char key;

    Print();

    system("cls");

    load();

    length=5;

    head.x=25;

    head.y=20;

    head.direction=RIGHT;

    Boarder();

    Food(); //to generate food coordinates initially

    life=3; //number of extra lives

    bend[0]=head;

    Move();   //initialing initial bend coordinate

    return 0;

}

void Move()
{
    int a,i;

    do{

        Food();
        fflush(stdin);

        len=0;

        for(i=0;i<30;i++)

        {

            body[i].x=0;

            body[i].y=0;

            if(i==length)

            break;

        }

        Delay(length);

        Boarder();

        if(head.direction==RIGHT)

            Right();

        else if(head.direction==LEFT)

            Left();

        else if(head.direction==DOWN)

            Down();

        else if(head.direction==UP)

            Up();

        ExitGame();

    }while(!kbhit());

    a=getch();

    if(a==27)

    {

        system("cls");

        exit(0);

    }
    key=getch();

    if((key==RIGHT&&head.direction!=LEFT&&head.direction!=RIGHT)||(key==LEFT&&head.direction!=RIGHT&&head.direction!=LEFT)||(key==UP&&head.direction!=DOWN&&head.direction!=UP)||(key==DOWN&&head.direction!=UP&&head.direction!=DOWN))

    {

        bend_no++;

        bend[bend_no]=head;

        head.direction=key;

        if(key==UP)

            head.y--;

        if(key==DOWN)

            head.y++;

        if(key==RIGHT)

            head.x++;

        if(key==LEFT)

            head.x--;

        Move();

    }

    else if(key==27)

    {

        system("cls");

        exit(0);

    }

    else

    {

        printf("\a");

        Move();

    }
}

void gotoxy(int x, int y)
{

 COORD coord;

 coord.X = x;

 coord.Y = y;

 SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), coord);

}
void GotoXY(int x, int y)
{
    HANDLE a;
    COORD b;
    fflush(stdout);
    b.X = x;
    b.Y = y;
    a = GetStdHandle(STD_OUTPUT_HANDLE);
    SetConsoleCursorPosition(a,b);
 }
 void sleep(unsigned int mseconds)
{
    clock_t goal = mseconds + clock();
    while (goal > clock());
}
void load(){
    int row,col,r,c,q;
    gotoxy(36,14);
    printf("loading...");
    gotoxy(30,15);
    for(r=1;r<=20;r++){
    sleep(200);//to display the character slowly
    printf("%c",177);}
    getch();
}
void Down()
{
    int i;
    for(i=0;i<=(head.y-bend[bend_no].y)&&len<length;i++)
    {
        GotoXY(head.x,head.y-i);
        {
            if(len==0)
                printf("v");
            else
                printf("*");
        }
        body[len].x=head.x;
        body[len].y=head.y-i;
        len++;
    }
    Bend();
    if(!kbhit())
        head.y++;
}
void Delay(long double k)
{
    Score();
    long double i;
    for(i=0;i<=(10000000);i++);
}
void ExitGame()
{
    int i,check=0;
    for(i=4;i<length;i++)   //starts with 4 because it needs minimum 4 element to touch its own body
    {
        if(body[0].x==body[i].x&&body[0].y==body[i].y)
        {
            check++;    //check's value increases as the coordinates of head is equal to any other body coordinate
        }
        if(i==length||check!=0)
            break;
    }
    if(head.x<=10||head.x>=70||head.y<=10||head.y>=30||check!=0)
    {
        life--;
        if(life>=0)
        {
            head.x=25;
            head.y=20;
            bend_no=0;
            head.direction=RIGHT;
            Move();
        }
        else
        {
            system("cls");
            printf("All lives completed\nBetter Luck Next Time!!!\nPress any key to quit the game\n");
            record();
            exit(0);
        }
    }
}
void Food()
{
    if(head.x==food.x&&head.y==food.y)
    {
        length++;
        time_t a;
        a=time(0);
        srand(a);
        food.x=rand()%70;
        if(food.x<=10)
            food.x+=11;
        food.y=rand()%30;
        if(food.y<=10)

            food.y+=11;
    }
    else if(food.x==0)/*to create food for the first time coz global variable are initialized with 0*/
    {
        food.x=rand()%70;
        if(food.x<=10)
            food.x+=11;
        food.y=rand()%30;
        if(food.y<=10)
            food.y+=11;
    }
}
void Left()
{
    int i;
    for(i=0;i<=(bend[bend_no].x-head.x)&&len<length;i++)
    {
        GotoXY((head.x+i),head.y);
       {
                if(len==0)
                    printf("<");
                else
                    printf("*");
        }
        body[len].x=head.x+i;
        body[len].y=head.y;
        len++;
    }
    Bend();
    if(!kbhit())
        head.x--;

}
void Right()
{
    int i;
    for(i=0;i<=(head.x-bend[bend_no].x)&&len<length;i++)
    {
        //GotoXY((head.x-i),head.y);
        body[len].x=head.x-i;
        body[len].y=head.y;
        GotoXY(body[len].x,body[len].y);
        {
            if(len==0)
                printf(">");
            else
                printf("*");
        }
        /*body[len].x=head.x-i;
        body[len].y=head.y;*/
        len++;
    }
    Bend();
    if(!kbhit())
        head.x++;
}
void Bend()
{
    int i,j,diff;
    for(i=bend_no;i>=0&&len<length;i--)
    {
            if(bend[i].x==bend[i-1].x)
            {
                diff=bend[i].y-bend[i-1].y;
                if(diff<0)
                    for(j=1;j<=(-diff);j++)
                    {
                        body[len].x=bend[i].x;
                        body[len].y=bend[i].y+j;
                        GotoXY(body[len].x,body[len].y);
                        printf("*");
                        len++;
                        if(len==length)
                            break;
                    }
                else if(diff>0)
                    for(j=1;j<=diff;j++)
                    {
                        /*GotoXY(bend[i].x,(bend[i].y-j));
                        printf("*");*/
                        body[len].x=bend[i].x;
                        body[len].y=bend[i].y-j;
                        GotoXY(body[len].x,body[len].y);
                        printf("*");
                        len++;
                        if(len==length)
                            break;
                    }
            }
        else if(bend[i].y==bend[i-1].y)
        {
            diff=bend[i].x-bend[i-1].x;
            if(diff<0)
                for(j=1;j<=(-diff)&&len<length;j++)
                {
                    /*GotoXY((bend[i].x+j),bend[i].y);
                    printf("*");*/
                    body[len].x=bend[i].x+j;
                    body[len].y=bend[i].y;
                    GotoXY(body[len].x,body[len].y);
                        printf("*");
                   len++;
                   if(len==length)
                           break;
               }
           else if(diff>0)
               for(j=1;j<=diff&&len<length;j++)
               {
                   /*GotoXY((bend[i].x-j),bend[i].y);
                   printf("*");*/
                   body[len].x=bend[i].x-j;
                   body[len].y=bend[i].y;
                   GotoXY(body[len].x,body[len].y);
                       printf("*");
                   len++;
                   if(len==length)
                       break;
               }
       }
   }
}
void Boarder()
{
   system("cls");
   int i;
   GotoXY(food.x,food.y);   /*displaying food*/
       printf("F");
   for(i=10;i<71;i++)
   {
       GotoXY(i,10);
           printf("!");
       GotoXY(i,30);
           printf("!");
   }
   for(i=10;i<31;i++)
   {
       GotoXY(10,i);
           printf("!");
       GotoXY(70,i);
       printf("!");
   }
}
void Print()
{
   //GotoXY(10,12);
   printf("\tWelcome to the mini Snake game.(press any key to continue)\n");
  getch();
   system("cls");
   printf("\tGame instructions:\n");
   printf("\n-> Use arrow keys to move the snake.\n\n-> You will be provided foods at the several coordinates of the screen which you have to eat. Everytime you eat a food the length of the snake will be increased by 1 element and thus the score.\n\n-> Here you are provided with three lives. Your life will decrease as you hit the wall or snake's body.\n\n-> YOu can pause the game in its middle by pressing any key. To continue the paused game press any other key once again\n\n-> If you want to exit press esc. \n");
   printf("\n\nPress any key to play game...");
   if(getch()==27)
   exit(0);
}
void record(){
   char plname[20],nplname[20],cha,c;
   int i,j,px;
   FILE *info;
   info=fopen("record.txt","a+");
   getch();
   system("cls");
   printf("Enter your name\n");
   scanf("%[^\n]",plname);
   //************************
   for(j=0;plname[j]!='\0';j++){ //to convert the first letter after space to capital
   nplname[0]=toupper(plname[0]);
   if(plname[j-1]==' '){
   nplname[j]=toupper(plname[j]);
   nplname[j-1]=plname[j-1];}
   else nplname[j]=plname[j];
   }
   nplname[j]='\0';
   //*****************************
   //sdfprintf(info,"\t\t\tPlayers List\n");
   fprintf(info,"Player Name :%s\n",nplname);
    //for date and time

   time_t mytime;
  mytime = time(NULL);
  fprintf(info,"Played Date:%s",ctime(&mytime));
     //**************************
     fprintf(info,"Score:%d\n",px=Scoreonly());//call score to display score
     //fprintf(info,"\nLevel:%d\n",10);//call level to display level
   for(i=0;i<=50;i++)
   fprintf(info,"%c",'_');
   fprintf(info,"\n");
   fclose(info);
   printf("wanna see past records press 'y'\n");
   cha=getch();
   system("cls");
   if(cha=='y'){
   info=fopen("record.txt","r");
   do{
       putchar(c=getc(info));
       }while(c!=EOF);}
     fclose(info);
}
int Score()
{
   int score;
   GotoXY(20,8);
   score=length-5;
   printf("SCORE : %d",(length-5));
   score=length-5;
   GotoXY(50,8);
   printf("Life : %d",life);
   return score;
}
int Scoreonly()
{
int score=Score();
system("cls");
return score;
}
void Up()
{
   int i;
   for(i=0;i<=(bend[bend_no].y-head.y)&&len<length;i++)
   {
       GotoXY(head.x,head.y+i);
       {
           if(len==0)
               printf("^");
           else
               printf("*");
       }
       body[len].x=head.x;
       body[len].y=head.y+i;
       len++;
   }
   Bend();
   if(!kbhit())
       head.y--;
}

Answer 1

Things that could be improved:

Portability:

• Every time you add an #import to the top of your C file, you potentially create a dependency. For example: #include <windows.h> creates a dependency that the program can only be compiled on a Windows system.

  #include <stdio.h>
  #include <time.h>
  #include <stdlib.h>
  #include <conio.h>
  #include <time.h>
  #include <ctype.h>
  #include <time.h>
  #include <windows.h>
  #include <process.h>
  #include <unistd.h>
  

  You should always try to create a program so that it is as portable as possible, and can be played on a variety of systems. Right now, your game can only be played on a few select systems.

Conventions/Standards:

• You don't follow proper C naming conventions for method names.

  void Delay(long double);
  void Move();
  void Food();
  int Score();
  void Print();
  void gotoxy(int x, int y);
  void GotoXY(int x,int y);
  void Bend();
  void Boarder();
  void Down();
  void Left();
  void Up();
  void Right();
  void ExitGame();
  int Scoreonly();
  

  Either use camelCase, or snake_case with method names.

• You should have unique method names.

  void gotoxy(int x, int y);
  void GotoXY(int x,int y);
  

  Be more expressive with your function naming.

• You don't typedef a struct in the standard way, nor do you use proper naming conventions of typedef structs.

  struct coordinate{
      int x;
      int y;
      int direction;
  };
  
  typedef struct coordinate coordinate;
  

  You can combine these two together for the proper definition of a typedef struct. Also, you should always capitalize the first letter of the typedef struct name.

  typedef struct
  {
      int x;
      int y;
      int direction;
  } Coordinate;
  

• Don't use a for loop in the place of sleep().

  for(i=0;i<=(10000000);i++);
  

  There are many problems with busy waiting instead of using sleep(). See this question for more information.

• If you don't take in any variables as parameters, you should declare them as void.

  int main(void)
  

• Define i inside of your for loop.^(C99)

  for(int i = 4; i < length; i++)
  

Styling:

• You have way too much space in some areas of your program.

  int main()
  {
  
      char key;
  
      Print();
  
      system("cls");
  
      load();
  
      length=5;
  
      head.x=25;
  
      head.y=20;
  
      head.direction=RIGHT;
  
      Boarder();
  
      Food(); //to generate food coordinates initially
  
      life=3; //number of extra lives
  
      bend[0]=head;
  
      Move();   //initialing initial bend coordinate
  
      return 0;
  
  } 
  

  I'm all for using whitespace, but there are limits to everything. Cut back on it a bit, right now the amount of whitespace you are using makes this program unreadable.

Syntax:

• You have some #defines that are related to each other.

  #define UP 72
  #define DOWN 80
  #define LEFT 75
  #define RIGHT 77
  

  These are all related to each other because they are all directions. Therefore, we can group them together in an enum.

  typedef enum
  {
      UP = 72;
      DOWN = 80;
      LEFT = 75;
      RIGHT = 77;
  } Direction;
  

• Use puts() instead of printf() when you are not formatting strings.

Answer 2

The "annoying blinking" is probably caused by your calling system("cls"); at the top of your Boarder() function, which you call repeatedly from inside your Move() function. It would blink less if you didn't clear the screen every time your redraw the border, and/or if you didn't redraw the border for every move.