NCTU LAB 11/12 SNAKE

#include <stdio.h>
#include <ctime>
#include <conio2.h>
#include <cstdlib>

#define MAXX 120
#define MAXY 30


void show (int x, int y, int dir, int len, int sx, int sy){
    for (int i=0; i<len; i++){
        switch (dir){
            case 1:
                gotoxy(x,(y-i-1)%MAXY+1); //DOWN
                break;
            case 2:
                gotoxy(((x+i+MAXX-1)%MAXX+1),y); //LEFT
                break;
            case 3:
                gotoxy(x,(y+i+MAXY-1)%MAXY+1); //UP
                break;
            case 4:
                gotoxy(((x-i-1)%MAXX+1),y); //RIGHT
                break;
        }
        if(i==0){
            textcolor(YELLOW);
            textbackground(LIGHTRED);
            printf("A");
        }else{
            textbackground(LIGHTBLUE);
            printf(" ");
        }
    }
    switch (dir){
        case 1:
            gotoxy(x,y%MAXY-1);
            break;
        case 2:
            gotoxy(x%MAXX+1,y);
            break;
        case 3:
            gotoxy(x,y%MAXY+1);
            break;
        case 4:
            gotoxy(x%MAXX-1,y);
            break;
    }
    textattr((YELLOW<<4) + BLACK);
    gotoxy(sx, sy);
    printf("0");
}
void control(int *dir){
    char key;
    if (kbhit){
        key = getch();
        switch(key){
            case 'w':
                *dir = 3;
                break;
            case 'a':
                *dir = 2;
                break;
            case 's':
                *dir = 1;
                break;
            case 'd':
                *dir = 4;
                break;
            case 'p':
                exit(0);
                break;
            default:
                gotoxy(MAXX/2,MAXY/2);
                printf("USE ONLY LOWERCASE W/A/S/D");
        }
    }
}
void move(int dir, int *x, int *y){
    switch(dir){
        case 1:
            *y+=1;
            if(*y==MAXY+1){
                *y=0;
            }
            break;
        case 2:
            *x-=1;
            if(*x==0){
                *x=MAXX
            }
            break;
        case 3:
            *y-=1;
            if(*y==0){
                *y=MAXY;
            }
            break;
        case 4:
            *x+=1;
            if(*x==MAXX+1){
                *x=0;
            }
            break;
    }
}
void gen_stone(int *x, int*y, int *flag){
    if(*flag==0){
        *x = rand()%MAXX;
        *y = rand()%MAXY;
        *flag = 1;
    }
}
void eat(int x, int y, int *len, int sx, int sy, int *sflag){
    if(x==sx && y==sy){
        *len+=1;
        *sflag = 0;
    }
}

int main(){
    int x=20, y=20, dir=1, len=1;
    int sx, sy, sflag=0;

    srand(time(NULL));
    while(1){
        textbackground(BLACK);
        clrscr();
        gen_stone(&sx, &sy, &sflag);
        control(&dir);
        move(dir, &x, &y);
        eat(x,y,&len,sx,sy,&sflag);
        show (x,y,dir,len,sx,sy);
        _sleep(500);
    }
    return 0;
}