1.        左边为head,右边为tail

        定义相反数在abs（）绝对值函数中实现

2. 在转向函数turn()中，如果绝对值不相等的时候才赋予方向的值

3.贪吃蛇吃食物的思路

3.1 初始化食物initFood(), 蛇碰到食物函数hasFood（）,在移动过程中if函数把蛇的尾巴的行和列传过来调用hasFood（）来初始化食物initFood()

3.2 static 是静态数值

   

3.2食物的随机

3.3撞到自己的时候死亡

在ifSnakedie（）函数中，第一个if是判断是否撞墙，因为while每次都会遍历完到自己，

为了防止遍历到自己，p->next !=NULL 忽略自己与自己比较，

在移动蛇的函数里面做修改

4.完整贪吃蛇代码

#include <curses.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>#define UP       1
#define DOWN    -1
#define LEFT     2
#define RIGHT   -2void initNcurses()
{initscr();keypad(stdscr,1);noecho();
}struct Snake
{int hang;int lie;struct Snake *next;};struct Snake *head = NULL;
struct Snake *tail = NULL;
int key;
int dir;struct Snake food;void initFood()
{int x = rand()%20;int y = rand()%20;food.hang = x;food.lie = y;
}int hasSnakeNode(int i,int j){       // da yin she shen tistruct Snake *p;p = head;  //ding tou while(p != NULL){if(p -> hang == i && p ->lie == j){return 1;}p = p ->next;}return 0;
}int hasFood(int i,int j)
{if(food.hang == i && food.lie == j){return 1;}return 0;
}void gamePic()
{int hang;int lie;move(0,0);for(hang = 0;hang<20;hang++){if(hang==0){for(lie=0;lie<20;lie++){printw("--");}printw("\n");}if(hang>= 0 || hang <=18){for(lie = 0;lie<=20;lie++){if(lie == 0 || lie == 20){printw("|");}else if(hasSnakeNode(hang,lie)){printw("[]");}else if(hasFood(hang,lie)){printw("##");}else{printw("  ");}}printw("\n");}if(hang == 19){for(lie=0;lie<20;lie++){printw("--");}printw("\n");printw("by caoshupei,key= %d\n",key);}}
}
void addNode()
{struct Snake *new = (struct Snake *)malloc(sizeof(struct Snake));new -> next =NULL;switch(dir){case UP:new -> hang = tail -> hang-1;new -> lie = tail -> lie;break;case DOWN:new -> hang = tail -> hang+1;new -> lie = tail ->lie;break;case LEFT:new -> hang = tail -> hang;new ->lie = tail -> lie-1;break;case RIGHT:new -> hang = tail -> hang;new -> lie = tail -> lie+1;break;}tail -> next = new;tail = new;
}void deleteNode()
{struct Snake *p;p = head;head = head ->next;free(p);    // fang zhi zao cheng hen duo kong yu de jie dian
}void  initSnakebody()
{struct Snake *p;dir = RIGHT;//di yi ci yun xing shi bu hui zouwhile(head != NULL)                  //yi kai shi deng yu kong{                                  //zhuang qiao la jiu shi bu wei kong p = head;head = head -> next;
free(p);                   //shi fang nei cun}initFood();head = (struct Snake*)malloc(sizeof(struct Snake));head -> hang = 1;                   // gu ding chu shi weizhi head -> lie = 1;head -> next = NULL;               // tou de xie yi ge wei kongtail = head;                       // wei ba bian cheng touaddNode();                         // zeng jia jie dianaddNode();addNode();
}int ifSnakedie()
{struct Snake *p;p =head;if(tail -> hang <0|| tail ->lie == 0|| tail->hang == 20 ||tail->lie ==20){return 1;  // zhuang dao bian jie}while(p->next!=NULL){if(p -> hang == tail -> hang && p ->lie == tail-> lie){return 1;  // zhuang dao zi ji}p = p->next;}return 0;
}void moveSnake()
{struct Snake *p;struct Snake *new;addNode();if(hasFood(tail->hang,tail->lie)){initFood();}else{
deleteNode();}if(ifSnakedie()){initSnakebody();}
}void *refreshjiemian()
{while(1){moveSnake();gamePic();refresh();usleep(100000);}
}void turn(int direction)
{if(abs(dir) != abs(direction)){dir = direction;}
}void *changeDir()
{while(1){key = getch();switch(key){case KEY_DOWN:turn(DOWN);break;case KEY_UP:turn(UP);break;case KEY_LEFT:turn(LEFT);break;case KEY_RIGHT:turn(RIGHT);break;}}
}int main()
{pthread_t t1;pthread_t t2;initNcurses();initSnakebody();gamePic();pthread_create(&t1,NULL,refreshjiemian,NULL);sleep(1);pthread_create(&t2,NULL,changeDir,NULL);while(1);getch();endwin();return 0;
}