C language linked list to achieve snake game

  • 2020-05-30 20:49:49
  • OfStack

Read and learn the source code, and made simple comments and modifications, which only used linked list data structure, very suitable for beginners of C language learning to read.

The program can be compiled and run under VS2013.


#include<stdio.h>
#include<time.h>
#include<windows.h>
#include<stdlib.h>

#define U 1
#define D 2
#define L 3 
#define R 4  // The state of the snake, U On:   ; D : under; L: On the left  R Right: 

typedef struct SNAKE // The snake 1 A node 
{
 int x;
 int y;
 struct SNAKE *next;
}snake;

// The global variable //
int score = 0, add = 10;// Total score and food score per meal. 
int status, sleeptime = 200;// The time interval for each run 
snake *head, *food;// Snake head pointer, food pointer 
snake *q;// The pointer used to traverse the snake 
int endGamestatus = 0; // At the end of the game, 1 : hit a wall; 2 : bite yourself; 3 : quit the game voluntarily. 

// Declare all functions //
void Pos();
void creatMap();
void initSnake();
int biteSelf();
void createFood();
void cantCrossWall();
void snakeMove();
void pause();
void runGame();
void initGame();
void endGame();
void gameStart();

void Pos(int x, int y)// Set cursor position 
{
 COORD pos;
 HANDLE hOutput;
 pos.X = x;
 pos.Y = y;
 hOutput = GetStdHandle(STD_OUTPUT_HANDLE);// Returns a handle to a standard input, output, or error device / Handle to the error screen buffer 
 SetConsoleCursorPosition(hOutput, pos);
}

void creatMap()// Create a map 
{
 int i;
 for (i = 0; i<58; i += 2)// Print top and bottom border 
 {
  Pos(i, 0);
  printf(" s ");//1 Two squares take up two positions 
  Pos(i, 26);
  printf(" s ");
 }
 for (i = 1; i<26; i++)// Print left and right border 
 {
  Pos(0, i);
  printf(" s ");
  Pos(56, i);
  printf(" s ");
 }
}

void initSnake()// Initializes the snake body 
{
 snake *tail;
 int i;
 tail = (snake*)malloc(sizeof(snake));// Start with the tail of the snake x,y Set the starting position //
 tail->x = 24;
 tail->y = 5;
 tail->next = NULL;
 for (i = 1; i <= 4; i++)// The initial length is 4
 {
  head = (snake*)malloc(sizeof(snake));
  head->next = tail;
  head->x = 24 + 2 * i;
  head->y = 5;
  tail = head;
 }
 while (tail != NULL)// From head to toe, output snake body 
 {
  Pos(tail->x, tail->y);
  printf(" s ");
  tail = tail->next;
 }
}
//??
int biteSelf()// Judge if you bit yourself 
{
 snake *self;
 self = head->next;
 while (self != NULL)
 {
  if (self->x == head->x && self->y == head->y)
  {
   return 1;
  } 
  self = self->next;
 }
 return 0;
}

void createFood()// Random food 
{
 snake *food_1;
 srand((unsigned)time(NULL));// To prevent the same random number being generated each time, the seed is set to time
 food_1 = (snake*)malloc(sizeof(snake));
 while ((food_1->x % 2) != 0) // Make sure it's an even number, so that the food can meet the snake head 
 {
  food_1->x = rand() % 52 + 2;
 }
 food_1->y = rand() % 24 + 1;
 q = head;
 while (q->next == NULL)
 {
  if (q->x == food_1->x && q->y == food_1->y) // Determine if the body of the snake overlaps with the food 
  {
   free(food_1);
   createFood();
  }
  q = q->next;
 }
 Pos(food_1->x, food_1->y);
 food = food_1;
 printf(" s ");
}

void cantCrossWall()// Can't wear wall 
{
 if (head->x == 0 || head->x == 56 || head->y == 0 || head->y == 26)
 {
  endGamestatus = 1;
  endGame();
 }
}

void snakeMove()// Snakes' , on U, Under the D, On the left L, right R
{
 snake * nexthead;
 cantCrossWall();

 nexthead = (snake*)malloc(sizeof(snake));
 if (status == U)
 {
  nexthead->x = head->x;
  nexthead->y = head->y - 1;
  if (nexthead->x == food->x && nexthead->y == food->y)// If the 1 A food //
  {
   nexthead->next = head;
   head = nexthead;
   q = head;
   while (q != NULL)
   {
    Pos(q->x, q->y);
    printf(" s ");
    q = q->next;
   }
   score = score + add;
   createFood();
  }
  else            // If there is no food //
  {
   nexthead->next = head;
   head = nexthead;
   q = head;
   while (q->next->next != NULL)
   {
    Pos(q->x, q->y);
    printf(" s ");
    q = q->next;
   }
   Pos(q->next->x, q->next->y);
   printf(" ");
   free(q->next);
   q->next = NULL;
  }
 }
 if (status == D)
 {
  nexthead->x = head->x;
  nexthead->y = head->y + 1;
  if (nexthead->x == food->x && nexthead->y == food->y) // There is food 
  {
   nexthead->next = head;
   head = nexthead;
   q = head;
   while (q != NULL)
   {
    Pos(q->x, q->y);
    printf(" s ");
    q = q->next;
   }
   score = score + add;
   createFood();
  }
  else        // There is no food 
  {
   nexthead->next = head;
   head = nexthead;
   q = head;
   while (q->next->next != NULL)
   {
    Pos(q->x, q->y);
    printf(" s ");
    q = q->next;
   }
   Pos(q->next->x, q->next->y);
   printf(" ");
   free(q->next);
   q->next = NULL;
  }
 }
 if (status == L)
 {
  nexthead->x = head->x - 2;
  nexthead->y = head->y;
  if (nexthead->x == food->x && nexthead->y == food->y)// There is food 
  {
   nexthead->next = head;
   head = nexthead;
   q = head;
   while (q != NULL)
   {
    Pos(q->x, q->y);
    printf(" s ");
    q = q->next;
   }
   score = score + add;
   createFood();
  }
  else        // There is no food 
  {
   nexthead->next = head;
   head = nexthead;
   q = head;
   while (q->next->next != NULL)
   {
    Pos(q->x, q->y);
    printf(" s ");
    q = q->next;
   }
   Pos(q->next->x, q->next->y);
   printf(" ");
   free(q->next);
   q->next = NULL;
  }
 }
 if (status == R)
 {
  nexthead->x = head->x + 2;
  nexthead->y = head->y;
  if (nexthead->x == food->x && nexthead->y == food->y)// There is food 
  {
   nexthead->next = head;
   head = nexthead;
   q = head;
   while (q != NULL)
   {
    Pos(q->x, q->y);
    printf(" s ");
    q = q->next;
   }
   score = score + add;
   createFood();
  }
  else           // There is no food 
  {
   nexthead->next = head;
   head = nexthead;
   q = head;
   while (q->next->next != NULL)
   {
    Pos(q->x, q->y);
    printf(" s ");
    q = q->next;
   }
   Pos(q->next->x, q->next->y);
   printf(" ");
   free(q->next);
   q->next = NULL;
  }
 }
 if (biteSelf() == 1)  // Judge if you're going to bite yourself 
 {
  endGamestatus = 2;
  endGame();
 }
}

void pause()// suspended 
{
 while (1)
 {
  Sleep(300);
  if (GetAsyncKeyState(VK_SPACE))
  {
   break;
  }

 }
}

void runGame()// Control of the game   
{

 Pos(64, 15);
 printf(" You can't walk through walls. You can't bite yourself \n");
 Pos(64, 16);
 printf(" With write . left . please . → separately control the movement of the snake .");
 Pos(64, 17);
 printf("F1  To speed up, F2  To slow down \n");
 Pos(64, 18);
 printf("ESC  : quit the game .space : pause the game .");
 Pos(64, 20);
 printf("C Language research centre  www.clang.cc");
 status = R;
 while (1)
 {
  Pos(64, 10);
  printf(" Score: %d ", score);
  Pos(64, 11);
  printf(" Score per food: %d points ", add);
  if (GetAsyncKeyState(VK_UP) && status != D)
  {
   status = U;
  }
  else if (GetAsyncKeyState(VK_DOWN) && status != U)
  {
   status = D;
  }
  else if (GetAsyncKeyState(VK_LEFT) && status != R)
  {
   status = L;
  }
  else if (GetAsyncKeyState(VK_RIGHT) && status != L)
  {
   status = R;
  }
  else if (GetAsyncKeyState(VK_SPACE))
  {
   pause();
  }
  else if (GetAsyncKeyState(VK_ESCAPE))
  {
   endGamestatus = 3;
   break;
  }
  else if (GetAsyncKeyState(VK_F1))
  {
   if (sleeptime >= 50)
   {
    sleeptime = sleeptime - 30;
    add = add + 2;
    if (sleeptime == 320)
    {
     add = 2;// To prevent to 1 And then we add it back again 
    }
   }
  }
  else if (GetAsyncKeyState(VK_F2))
  {
   if (sleeptime<350)
   {
    sleeptime = sleeptime + 30;
    add = add - 2;
    if (sleeptime == 350)
    {
     add = 1; // Guaranteed minimum score 1
    }
   }
  }
  Sleep(sleeptime);
  snakeMove();
 }
}

void initGame()// Start interface 
{
 Pos(40, 12);

 system("title C Language research centre  www.clang.cc");
 printf(" Welcome to the snake game! ");
 Pos(40, 25);
 printf("    C Language research centre  www.clang.cc.\n");
 system("pause");
 system("cls");
 Pos(25, 12);
 printf(" With write . left . please . → separately control the movement of the snake,  F1  To speed up, 2  To slow down \n");
 Pos(25, 13);
 printf(" The acceleration will result in higher scores. \n");
 system("pause");
 system("cls");
}

void endGame()// End of the game 
{

 system("cls");
 Pos(24, 12);
 if (endGamestatus == 1)
 {
  printf(" Sorry, you hit the wall. Game over .");
 }
 else if (endGamestatus == 2)
 {
  printf(" Sorry, you bit yourself. Game over .");
 }
 else if (endGamestatus == 3)
 {
  printf(" Your game is over. ");
 }
 Pos(24, 13);
 printf(" Your score is %d\n", score);
 while (getchar() != 'y')
 { 
  printf("close?[y]");
 }
 exit(0);
}

void gameStart()// Game initialization 
{
 system("mode con cols=100 lines=30");
 initGame();
 creatMap();
 initSnake();
 createFood();
}

int main()
{
 gameStart();
 runGame();
 endGame();
 return 0;
}


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