/*
{
 conio.h
 阻塞式： getch()：   从无回显的控制台获取字符。无缓冲区，只有当按下一个键才会执行后面的程序。
 非阻塞式： kbhit()    检测缓冲区中是否有字符；执行该函数后程序不会停下，而是继续执行下面的代码
 
 由于getch()和kbhit()已弃用，
 在编译时会产生警告，
 可以用_getch()和_kbhit()替换它们，
 或者在包含头文件前加上#pragma warning(disable : 4996)关闭警告
}



*/
#pragma warning(disable : 4996)   //用来关闭警告
#include<stdio.h>
#include <stdlib.h>
#include <conio.h>   //_kbhit()函数获取键盘事件
#include <time.h>
#include<Windows.h>


#define WIN_HEIGH  30   //窗口高度
#define WIN_WIDTH 105   //窗口宽度
#define G_HEIGHT  30   //游戏界面高度
#define G_WIDTH 80    //游戏界面宽度
#define STATUS int    //函数返回状态属性
#define SUCCESS 1    //执行成功
#define FAIL 0     //执行失败



typedef struct snake_node{    //蛇的某个点的信息
 char direct;    //即将前进的方向  udlr分别对应上下左右，刚吃掉的身体部分方向为o
 COORD postion;    //该点所在位置
 struct snake_node* next_node;  //下个节点的指针
}*Ps_node,S_node;

typedef struct snake {
 char head_type;   //蛇头的样子
 char body_type;   //蛇身的样子
 WORD color;    //颜色
 int level;    //等级
 int speed;    //速度
 int score;    //成绩
 int control;   //控制器 即按wasd进行移动，或者按上下左右进行移动 
 S_node head;   //蛇头
}*Psnake,Snake;    //蛇结构



// 0输出空格 -1输出#
char canvas[G_HEIGHT][G_WIDTH] ; //画布
int bean_count;      //已创建食物的数量
POINT reward_position;    //奖励的位置
int reward_time = -1000;   //奖励剩余时间
int run_snake_threads;    //正在运行的蛇的数量
char keyboard_out[2];    //键盘的输出控制器 keyboard_out[0],代表控制器1，keyboard_out[1],代表控制器2，

int init_snake_speed = 400;   //蛇的初始速度 ,例=400时，蛇0.4s前进一步

//关于颜色取值，请查看help.txt
void gotoxy(int x, int y);           //设置光标到指定位置
void setcolor(WORD wAttributes);         //设置输出颜色
void prc_toxy(char c, int x, int y);        //指定位置输出字符
void prs_toxy(char* str, int x, int y);        //指定位置输出字符串
void prc_colortoxy(char str, int x, int y, WORD wAttributes);  //在指定位置，以wAttributes颜色输出字符 
void prs_colortoxy(char* str, int x, int y, WORD wAttributes);  //在指定位置，以wAttributes颜色输出字符字符串


void one_play_mod();  //进入单人模式
void two_play_mod();  //进入双人模式


/***********************

 函数名：init_system
 功能：
   获取窗口句柄
   设置控制台颜色和大小
   隐藏光标显示

************************/
void init_system();



/***********************
 
 函数名：init_snode
 功能：初始化新的身体节点
 输入参数：
  direct:这个节点的下一个运动方向；
  snake_x,snake_y:这个节点的位置(x,y)
  next_node:下一个节点的指针
 返回值：
  Ps_node:返回已初始化的节点的指针

************************/
Ps_node init_snode(Ps_node n_snode,char drect,int x,int y,Ps_node next_node);


/************************

 函数名:init_snake
 功能：初始化蛇的相关参数，并为其创建身体，长度为三
 输入参数：
   she:  要初始化的蛇指针
   color:  蛇的颜色
   head_type:  用该字符显示蛇的身体
   x,y:  蛇最开始的位置
   direct:  默认前进方向
   control: 移动蛇的方式：默认1为WASD键，2为方向键盘上下左右键
 返回值：初始化后的蛇指针

**************************/
Psnake init_snake(Psnake she ,WORD color,char head_type,char body_type,int x,int y, char direct, int control);  //初始化小蛇


DWORD WINAPI Run_Snake_Thread(LPVOID lpParam);    //线程：运行一条蛇
DWORD WINAPI Del_reward_Thread(LPVOID lpParam);    //线程：生成奖励后，一段时间内不迟到奖励会消失
DWORD WINAPI Render_Thread(LPVOID lpParam);     //线程：用来渲染，游戏运行时，所有的打印显示由该进程完成
DWORD WINAPI Keyboard_Thread(LPVOID lpParam);    //线程：游戏运行时，监听按键输入，并设置keyboard_out




/************************

 函数名:get_canvas_toxy
 功能： 获取画布上该点的值
 输入参数：postion 
 返回值：char类型，画布上该点的值

************************/
char get_canvas_toxy(COORD postion);



/***********************

 函数名:snode_gonext
 功能： 蛇身体上的点移动到下个位置
 输入参数：
  snode：要移动的点
  direct:要移动的方向
 返回值：char ,未移动前，该点要前进的方向
************************/
char snode_gonext(Ps_node snode, char direct);



/***********************
 
 函数名:snake_gonext
 功能： 蛇移动到下个位置
 输入参数：
  she：要移动的蛇
  direct：蛇头移动的方向
 返回值：无
************************/
void snake_gonext(Psnake she, char direct);


/********************
 
 函数名：init_canvas
 功能： 初始化画布，并为画布设置边框
 输入参数： 无
 返回值： 无

********************/
void init_canvas();


void draw_wall();      //在canvas上设置边框位置

 
/***********************

 函数名:snaketocanvas
 功能：将蛇的坐标信息拷贝到画布canvas上,在canvas上删除原来的位置信息,
 输入参数：she ：要拷贝的蛇的指针

***********************/
void snaketocanvas(Psnake she);

/**************************
 
 函数名：eat_node
 功能：蛇吃食物，并把它加入蛇身，并增加成绩，触发升级加速
  (注：加入到蛇身后该点的位置还在原来的地方，需要身体都经过那里后长度才会增加)
 输入参数：
   she:吃食物的那条蛇
   position：食物的位置

**************************/
void eat_node(Psnake she, COORD postion);



/**********************
 
 函数名：create_bean
 功能：在画布的一个随机位置创建豆

 返回值：
   status：返回是否创建成功
**********************/
STATUS createrand_bean(); 

/**********************
 
 函数名：free_snake
 功能：释放小蛇的内存
 输入参数：
   she：要释放内存的小蛇

************************/
void free_snake(Psnake she);

void  menu();   //开始菜单， 用来选择模式，单人或者双人

void show_menu(int flag);  //根据不同的flag显示不同的菜单

HANDLE handle;
int main() {
 init_system();
 menu();
 return 0;
}
void init_system() {
 system("color F0 ");
 handle = GetStdHandle(STD_OUTPUT_HANDLE);//获取窗口句柄
 char chCmd[32];
 sprintf(chCmd, "mode con cols=%d lines=%d", WIN_WIDTH, WIN_HEIGH);  //设置控制台大小
 system(chCmd);
 CONSOLE_CURSOR_INFO cursor_info = { 1,0 };   //设置光标不可见，第一个值为光标厚度，第二个值为光标是否显示
 SetConsoleCursorInfo(handle, &cursor_info);   // 
 srand((int)time(NULL));        //初始化随机数种子
}
void menu() {
 int ch1, ch2;
 int flag = 1;  //标志当前选择模式
 show_menu(flag);
 while (1) {
  ch1 = _getch();
  if (ch1 == 13) {
   printf("此处是进入函数\n");
   if (flag == 1)
    one_play_mod();
   else if (flag == 2)
    two_play_mod();
   else {
    system("cls");
    printf("退出\n");
    break;
   }
  }
  if (ch1==224) {
   ch2 = _getch();
   if (ch2 == 72) {
    flag = (flag + 2)% 3;
   }
   else if (ch2 == 80) {
    flag = (flag + 4) % 3;
   }
  }
  show_menu(flag);
 }
}
void show_menu(int flag) {
 char gamename[30] = "贪      吃      蛇";
 char mod1[20] = "单人模式";
 char mod2[20] = "双人模式";
 char modexit[20] = "退出";
 int xstr = (WIN_WIDTH - strlen(mod1)) / 2;   //要打印选项的位置x列
 int ystr;           //要打印选项的位置y行
 WORD color[3] = {0xf0,0xf0,0xf0};           //要设置的颜色
 system("cls");
 setcolor(0xf0);
 prs_toxy(gamename, (WIN_WIDTH - strlen(gamename) )/ 2, 5);
 color[flag] = FOREGROUND_RED | 0xf0;
 prs_colortoxy(mod1, (WIN_WIDTH - strlen(mod1)) / 2, 11, color[1]);
 prs_colortoxy(mod2, (WIN_WIDTH - strlen(mod2)) / 2, 13, color[2]);
 prs_colortoxy(modexit, (WIN_WIDTH - strlen(modexit)) / 2, 15, color[0]);
 if (flag == 1) ystr = 11; else if (flag == 2) ystr = 13; else ystr = 15;  //设置箭头位于哪一行
 prs_colortoxy("→", xstr - 4, ystr, color[flag]);
 gotoxy(0, 0);
}
void gotoxy(int x, int y) {
 COORD pos;
 pos.X = x;
 pos.Y = y;
 SetConsoleCursorPosition(handle, pos);
}

void setcolor(WORD wAttributes) {
 SetConsoleTextAttribute(handle, wAttributes);
}
void prc_toxy(char c, int x, int y) {
 gotoxy(x, y);
 printf("%c", c);
}

void prs_toxy(char* str, int x, int y) {
 gotoxy(x, y);
 printf("%s", str);
}
void prc_colortoxy(char c, int x, int y, WORD wAttributes) {
 gotoxy(x, y);
 SetConsoleTextAttribute(handle, wAttributes);
 printf("%c", c);
}
void prs_colortoxy(char* str, int x, int y, WORD wAttributes) {
 gotoxy(x, y);
 SetConsoleTextAttribute(handle, wAttributes);
 printf("%s", str);
}
Ps_node init_snode(Ps_node n_snode, char drect, int x, int y, Ps_node next_node) {
 n_snode->direct = drect;
 n_snode->postion.X = x;
 n_snode->postion.Y = y;
 n_snode->next_node = next_node;
 return n_snode;
}
Psnake init_snake(Psnake she , WORD color, char head_type, char body_type, int x, int y, char direct,int control) {
 int ax=x,ay=y,bx=x,by=y;
 she->head_type = head_type;
 she->body_type = body_type;
 she->color = color;
 she->control = control; 
 she->level = 1;
 she->speed = init_snake_speed;
 she->score = 0;
 Ps_node s1 = (Ps_node)malloc(sizeof(S_node));
 Ps_node s2 = (Ps_node)malloc(sizeof(S_node)); 
 switch (direct)
 {
 case 'l':
  ax = x + 2; bx = x + 1;
  break;
 case 'r':
  ax = x - 2; bx = x - 1;
  break;
 case 'u':
  ay = y + 2; by = y + 1;
  break;
 case 'd':
  ay = y - 2; by = y - 1;
  break;
 default:
  break;
 }
 init_snode(s2, direct, ax, ay, NULL);     //要根据方向设置下一个节点的位置
 init_snode(s1, direct, bx , by, s2);
 init_snode(&she->head, direct, x, y,s1);
 return she;
}
void one_play_mod() {
 HANDLE hThread;
 HANDLE hThread_render;
 HANDLE hT_getkey;
 Snake xiaoshe;
 system("cls");
 bean_count = 0;
 init_canvas();
 init_snake(&xiaoshe,0xf2, '@','*', G_WIDTH/2, G_HEIGHT/2, 'r', 2);
 snaketocanvas(&xiaoshe);
 createrand_bean();
 run_snake_threads = 1;
 draw_wall();
 hThread = CreateThread(NULL, 0, Run_Snake_Thread,(LPVOID)&xiaoshe, 0, NULL);
 hThread_render = CreateThread(NULL, 0, Render_Thread, (LPVOID)&xiaoshe, 0, NULL);
 hT_getkey= CreateThread(NULL, 0,Keyboard_Thread, NULL, 0, NULL);
 WaitForSingleObject(hThread, INFINITE);
 run_snake_threads = 0;
 WaitForSingleObject(hT_getkey, INFINITE);
 WaitForSingleObject(hThread_render, INFINITE);
 CloseHandle(hThread);
 CloseHandle(hT_getkey);
 CloseHandle(hThread_render);
 gotoxy(G_WIDTH / 2-2, G_HEIGHT / 2);
 printf("游戏结束\n");
 Sleep(2000);
}
void two_play_mod() {
 HANDLE hThread_a;
 HANDLE hThread_b;
 HANDLE hThread_render;
 HANDLE hT_getkey;
 Snake she[2];
 system("cls");
 bean_count = 0;
 init_canvas();
 init_snake(&she[0], 0xf2, '@', '*', G_WIDTH / 2-4, G_HEIGHT / 2 -4, 'r', 2);
 init_snake(&she[1], 0xE5, 'U', 'S', G_WIDTH / 2, G_HEIGHT / 2, 'l', 1);
 snaketocanvas(&she[0]);
 snaketocanvas(&she[1]);
 draw_wall();
 createrand_bean();
 /*createrand_bean();  //创建多个食物
 createrand_bean();
 createrand_bean();*/
 run_snake_threads = 2;
 hThread_b = CreateThread(NULL, 0, Run_Snake_Thread, (LPVOID)&she[0], 0, NULL);
 hThread_a = CreateThread(NULL, 0, Run_Snake_Thread, (LPVOID)&she[1], 0, NULL);
 hThread_render= CreateThread(NULL, 0, Render_Thread, (LPVOID)&she, 0, NULL);
 hT_getkey = CreateThread(NULL, 0, Keyboard_Thread, NULL, 0, NULL);
 WaitForSingleObject(hThread_a, INFINITE);
 WaitForSingleObject(hThread_b, INFINITE);
 run_snake_threads = 0;
 WaitForSingleObject(hT_getkey, INFINITE);
 WaitForSingleObject(hThread_render, INFINITE);
 CloseHandle(hThread_a);
 CloseHandle(hThread_b);
 CloseHandle(hT_getkey);
 CloseHandle(hThread_render);
 gotoxy(G_WIDTH / 2, G_HEIGHT / 2);
 printf("游戏结束\n");
 Sleep(1000);
}
DWORD WINAPI Keyboard_Thread(LPVOID lpParam) {
 int ch1;
 int ch2;
 keyboard_out[0] = 'n'; keyboard_out[1] = 'n';  
 while (run_snake_threads > 0) {
  while (_kbhit())
  {
   ch1 = _getch();
   switch (ch1)
   {
   case 'w':
    keyboard_out[0] = 'u';
    break;
   case 's':
    keyboard_out[0] = 'd';
    break;
   case 'd':
    keyboard_out[0] = 'r';
    break;
   case 'a':
    keyboard_out[0] = 'l';
    break;
   case 224:
    ch2 = _getch();
    switch (ch2)
    {
    case 72:
     keyboard_out[1] = 'u';
     break;
    case 80:
     keyboard_out[1] = 'd';
     break;
    case 77:
     keyboard_out[1] = 'r';
     break;
    case 75:
     keyboard_out[1] = 'l';
     break;
    default:
     break;
    }
    break;
   default:
    break;
   }
  }
  Sleep(50);
 }
}
char get_canvas_toxy(COORD postion) {
 return canvas[postion.Y][postion.X];
}
char snode_gonext(Ps_node snode, char direct) {
 char old_direct = snode->direct;
 snode->direct = direct;
 switch (direct)
 {
 case 'u':
  snode->postion.Y = snode->postion.Y - 1;
  break;
 case 'd':
  snode->postion.Y = snode->postion.Y + 1;
  break;
 case 'l':
  snode->postion.X = snode->postion.X - 1;
  break;
 case 'r':
  snode->postion.X = snode->postion.X + 1;
  break;
 default:
  break;
 }
 return old_direct;
}
void snake_gonext(Psnake she, char direct) {
 Ps_node temp=&she->head;
 Ps_node end = temp;
 char dta=direct;   //方向
 while (temp!=NULL)  //不处理最后一个节点
 {
  if(temp->next_node!=NULL && temp->next_node->direct=='n'){
   if (temp->postion.X == temp->next_node->postion.X && temp->postion.Y == temp->next_node->postion.Y) {
    dta = snode_gonext(temp, dta);
    temp->next_node->direct = dta;
   }else
    dta = snode_gonext(temp, dta);
   break;
  }
  dta=snode_gonext(temp, dta);
  temp = temp->next_node;
 }
 snaketocanvas(she);
}
void snaketocanvas(Psnake she) {
 Ps_node temp=&she->head;
 int i, j,x,y;
 char body_type = she->body_type;
 for (i = 1; i < G_HEIGHT - 1; i++)
  for (j = 1; j < G_WIDTH - 1; j++) 
   if (canvas[i][j] == she->head_type || canvas[i][j] == she->body_type)
    canvas[i][j] = '0';
 x = temp->postion.X;
 y = temp->postion.Y;
 while (temp->next_node != NULL) {
  canvas[temp->next_node->postion.Y][temp->next_node->postion.X] = body_type;
  temp = temp->next_node;
 }
 canvas[y][x] = she->head_type;   //单独处理蛇头,放在最后防止被覆盖
}
void draw_wall() {
 int i, j;
 setcolor(0xf0);
 gotoxy(0, 0);
 for (i = 0; i < G_HEIGHT; i++) {
  gotoxy(0, i);
  for (j = 0; j < G_WIDTH; j++) {
   if (canvas[i][j] == '#')
    printf("#");
   else
    printf(" ");
  }
 }
}
DWORD WINAPI Render_Thread(LPVOID lpParam) {
 Psnake shea = (Psnake)lpParam;
 Psnake sheb = (run_snake_threads==2)?((Psnake)lpParam+1):(shea);
 WORD color;
 char heada = shea->head_type;
 char headb = shea->head_type;
 char pr;
 char pr_score[50];
 char show_time[30];
 int snakes_counts = run_snake_threads;
 int i, j;
 if (snakes_counts == 1) {  //单人模式
  prs_colortoxy("player 1", G_WIDTH + 3, 6, 0xf0);
  prs_colortoxy("↑", G_WIDTH + 15, 5, 0xf0);
  prs_colortoxy("←↓→",G_WIDTH + 13, 6, 0xf0);
 }
 else {
  prs_colortoxy("player 1", G_WIDTH + 3, 6, 0xf0);
  prs_colortoxy("↑", G_WIDTH + 15, 5, 0xf0);
  prs_colortoxy("←↓→", G_WIDTH + 13, 6, 0xf0);

  prs_colortoxy("player 2", G_WIDTH + 3, 19, 0xf0);
  prs_colortoxy("W", G_WIDTH + 14, 18, 0xf0);
  prs_colortoxy("ASD", G_WIDTH + 13, 19, 0xf0);
 }
 while (run_snake_threads != 0)  //根据snake线程数结束循环
 {
  for (i = 1; i < G_HEIGHT-1; i++) {
   gotoxy(1, i);
   for (j = 1; j < G_WIDTH-1; j++) {
    switch (canvas[i][j])
    {
    case '@':   //蛇头
     color = (heada == '@') ? shea->color : sheb->color;
     pr = '@';
     break;
    case '*':   //蛇身
     color = (shea->body_type == '*') ? shea->color : sheb->color;
     pr = '*';
     break;
    case 'U':   //蛇头
     color = (shea->head_type == 'U') ? shea->color : sheb->color;
     pr = 'U';
     break;
    case 'S':   //蛇身
     color = (shea->body_type == 'S') ? shea->color : sheb->color;
     pr = 'S';
     break;
    case '$':   //豆子
     color = 0xf6;
     pr = '$';
     break;
    case '&':   //奖励
     color = 0xa4;
     pr = '&';
     break;
    case '0':
     color = 0xf0;
     pr = ' ';
     break;
    default:
     break;
    }
    setcolor(color);
    printf("%c", pr);
   }
  }
  sprintf(pr_score, "分数：      %d", shea->score);
  prs_colortoxy(pr_score, G_WIDTH + 3, 8, 0xf0);
  if (snakes_counts == 2) {
   sprintf(pr_score, "分数：      %d", sheb->score);
   prs_colortoxy(pr_score, G_WIDTH + 3, 21, 0xf0);
  }
  if (reward_time >= 0) {
   sprintf(show_time, "奖励剩余时间：%ds  ", reward_time / 1000);
   prs_colortoxy(show_time, G_WIDTH + 5, G_HEIGHT - 3, 0xf4);
  }
  else {
   prs_colortoxy("                    ", G_WIDTH + 5, G_HEIGHT - 3, 0xf4);
  }
  Sleep(50);  //显示频率
 }
}

STATUS createrand_bean() {
 int ran;  //canvas的第n个点为奖励位置
 int i,j,count,sum=0;
 char c = '$';
 HANDLE delrewarthread;
 
 for (i = 1; i < G_HEIGHT - 1; i++)
  for (j = 1; j < G_WIDTH - 1; j++)
   if (canvas[i][j] == '0') 
    sum++;
 if (sum == 0)
  return FAIL;
 if (bean_count % 5 == 0 && bean_count!=0) {
  ran = rand() % sum;
  count = 0;
  for (i = 1; i < G_HEIGHT - 1; i++)
   for (j = 1; j < G_WIDTH - 1; j++)
    if (canvas[i][j] == '0') {
     if (count == ran) {
      reward_position.x = j;
      reward_position.y = i;
      canvas[i][j] = '&';
      delrewarthread= CreateThread(NULL, 0, Del_reward_Thread, NULL, 0, NULL);
      CloseHandle(delrewarthread);
     }
     count++;
    }
 }
 bean_count++;
 ran = rand() % sum;
 count = 0;
 for (i = 1; i < G_HEIGHT - 1; i++)
  for (j = 1; j < G_WIDTH - 1; j++)
   if (canvas[i][j] == '0') {
    if (count == ran) {
     canvas[i][j] = c;
     return SUCCESS;
    }
    count++;
   }
 return FAIL;
}
void eat_node(Psnake she, COORD postion) {
 Ps_node end = &she->head;
 Ps_node s = (Ps_node)malloc(sizeof(S_node));
 while (end->next_node != NULL)
  end = end->next_node;
 init_snode(s,'n', postion.X, postion.Y, NULL);
 end->next_node = s;
 canvas[postion.Y][postion.X]=she->head_type;
 she->score++;
 if (she->score / 10 >= she->level) {
  she->level++;
  she->speed = (int)(she->speed * 0.75);
 }
}
void free_snake(Psnake she) {
 Ps_node body = she->head.next_node;
 Ps_node temp;
 while (body!=NULL)
 {
  temp = body->next_node;
  free(body);
  body = temp;
 }
}
DWORD WINAPI Run_Snake_Thread(LPVOID lpParam) {
 Psnake pshe = (Psnake)lpParam;
 char direct;
 COORD next_node;   //下一个蛇头位置
 char v_canvas;
 boolean end = 0;
 while (!end) {
  direct = pshe->head.direct;
  if (keyboard_out[pshe->control - 1] != 'n') {       //获取键盘输入的目的是，获取蛇要前往的下一个方向
   switch (keyboard_out[pshe->control - 1])  //输入方向与运行方向相反
   {
   case 'u':
    direct = (direct != 'd') ? 'u' : direct;
    break;
   case 'd':
    direct = (direct != 'u') ? 'd' : direct;
    break;
   case 'l':
    direct = (direct != 'r') ? 'l' : direct;
    break;
   case 'r':
    direct = (direct != 'l') ? 'r' : direct;
    break;
   default:
    break;
   }
   keyboard_out[pshe->control - 1] = 'n';
  }
  next_node = pshe->head.postion;
  switch (direct)
  {
  case 'u':
   next_node.Y = next_node.Y - 1;
   break;
  case 'd':
   next_node.Y = next_node.Y + 1;
   break;
  case 'l':
   next_node.X = next_node.X - 1;
   break;
  case 'r':
   next_node.X = next_node.X + 1;
   break;
  default:
   break;
  }
  v_canvas = get_canvas_toxy(next_node);
  switch (v_canvas)
  {
  case '0':      //表示该点安全，没有东西
   snake_gonext(pshe, direct);
   break;
  case '$':
   eat_node(pshe, next_node);
   snake_gonext(pshe, direct);
   end = !createrand_bean();
   break;
  case '&':      //吃下道具，触发减速
   eat_node(pshe, next_node);
   snake_gonext(pshe, direct);
   pshe->speed =(int) (pshe->speed * 1.25);
   break;
  default:
   end = 1;
   break;
  }
  Sleep(pshe->speed);
 }
 free_snake(pshe);  //这里只释放了蛇的身体其他信息仍保留
 Sleep(500);
 return 0;
}
DWORD WINAPI Del_reward_Thread(LPVOID lpParam) {
 
 reward_time = 10000;
 while (reward_time >=0)
 {
  if (canvas[reward_position.y][reward_position.x] == '&' && run_snake_threads>0) {
   Sleep(1000);
   reward_time = reward_time - 1000;
  }
  else
   break;
 }
 canvas[reward_position.y][reward_position.x] = '0';
 reward_time = -1000;
 return 0;
}
void init_canvas() {
 int i, j;
 for (i = 0; i < G_HEIGHT; i++)
  for (j = 0; j < G_WIDTH; j++) 
   canvas[i][j] = '0';
 for (i = 0; i < G_HEIGHT ; i++) {
  canvas[i][0] = '#';
  canvas[i][G_WIDTH - 1] = '#';
 }
 for (j = 0; j < G_WIDTH; j++) {
  canvas[0][j] = '#';
  canvas[G_HEIGHT  - 1][j] = '#';
 }
}