crappy C/ncurses implementation of "Snake" game

cnake.c

#include <ncurses.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

/* Functions */
void mvdraw(int,int,int);
void push(int);
void game_over(int);
void place_fruit(void);
int shift(void);

/* Variables */
int ate = 0;
int stgw = 65;
int stgh = 35;
int dir = 1; /* 0=up, 1=right 2=down, 3=left */
int headx = 12;
int heady = 12;
int tailx = 9;
int taily = 12;
int maxy;
int maxx;

int sp = 3;
int *trail;

int main(void) 
{
    // Get the time so we have a random number.
    // This way, rand will not generate the same sequence each run.
    time_t sec;
    time(&sec);
    srand((unsigned int) sec);

    initscr();
    noecho();
    keypad(stdscr, TRUE);
    raw();
    curs_set(0);
    start_color();

    // init color pairs.
    init_pair(0,COLOR_WHITE,COLOR_BLACK);
    init_pair(1,COLOR_RED,COLOR_BLACK);
    init_pair(2,COLOR_GREEN,COLOR_BLACK);
    init_pair(3,COLOR_BLUE,COLOR_BLACK);
    init_pair(4,COLOR_YELLOW,COLOR_BLACK);

    char currch;
    int ch,i,j,nextdir;

    getmaxyx(stdscr,maxy,maxx);

    attron(COLOR_PAIR(0));
    wborder(stdscr,124,124,45,45,43,43,43,43);

    mvprintw(2,5,"Welcome to Snake! Press any key to start.");
    mvprintw(3,5,"Press 'q' to quit.");
    mvprintw(4,5,"Press arrow keys to move.");

    refresh();
    ch = getch();

    clear();
    refresh();

    timeout(50);

    wborder(stdscr,124,124,45,45,43,43,43,43);

    mvdraw(12,12,64);
    mvdraw(12,11,64);
    mvdraw(12,10,64);
    mvdraw(12,9,64);

    trail = (int*) malloc(3*sizeof(int));
    trail[0]=1;
    trail[1]=1;
    trail[2]=1;

    refresh();

    int fr;
    for (fr=0;fr<15;fr++) {
        place_fruit();
    }

    for (;;) {
      fflush(stdin);
        ch = getch();

        if (ch == KEY_UP) dir = 0;
        else if (ch == KEY_DOWN) dir = 2;
        else if (ch == KEY_LEFT) dir = 3;
        else if (ch == KEY_RIGHT) dir = 1;	
	    else if (ch == 113 || ch == 81) break;
        else if (ch == 80 || ch  == 112) {
            timeout(-1);
            while ((ch = getch())) {
                if (ch == 80 || ch == 112) break;
            }
            if (dir % 2 == 0) timeout(80);
            else timeout(50);
        }

	    // Make sure they didn't try to go backwards
	    if (trail[sp-1]-2 == dir || trail[sp-1] == dir-2) dir = trail[sp-1];

	    // set a slower timeout speed when moving vertically,
	    // so it doesn't seem like the snake is moving faster
	    if (dir != trail[sp-1]) {
            if (dir % 2 == 0) timeout(80);
	        else timeout(50);
	    }

	    push(dir);
        
	    if (dir == 0) heady--;
    	else if (dir == 1) headx++;
    	else if (dir == 2) heady++;
    	else if (dir == 3) headx--;

    	/* Draw the tail first so 
    	 * the game doesn't get confused and think we hit 
    	 * the tail when we haven't
    	 * */
        if (ate == 0) {
            mvdraw(taily,tailx,32);
            nextdir = shift();
	        if (nextdir == 0) taily--;
	        else if (nextdir == 1) tailx++;
	        else if (nextdir == 2) taily++;
	        else if (nextdir == 3) tailx--;
	    }
	    else {
            ate = 0;
	        place_fruit();
	    }
	
	    // Check for collisions
	    currch = mvinch(heady,headx);
	    if (currch == 'O') {
	        // We got a fruit!
	        ate = 1;
	    }
	    else if (currch != ' ') {
	        // We hit something that is neither empty space nor a fruit
	        game_over(currch);
	        break;
	    }   

	    mvdraw(heady,headx,64);
        
	    refresh();
    }

    endwin();
    
    return 0; 
}

void mvdraw(int y, int x, int code)
{
    int pair = 0;
    if (code == 64) pair = 2;
    else if (code == 79) pair = 4;

    if (pair > 0) {
        move(y,x);
        addch(code|COLOR_PAIR(pair));
    }
    else {
        mvprintw(y,x,"%c",code);
    }
}

void push(int n)
{
    sp++;
    int *arr = (int*) malloc(sp*sizeof(int));

    memmove(arr,trail,(sp-1)*sizeof(int));

    free(trail);

    arr[sp-1] = n;
    trail = arr;
}

int shift(void) 
{
    sp--;
    int *arr = (int*) malloc(sp*sizeof(int));
    int start = trail[0];

    memmove(arr,trail+1,sp*sizeof(int));

    free(trail);
    trail = arr;

    return start;
}

void game_over(int curr) 
{
    attron(COLOR_PAIR(1));
    mvprintw(10,10,"You died! You were %d snake-units long!",++sp);
    mvprintw(11,10,"Way to go, stud!");
    timeout(-1);
    refresh();
    int ch = getch();
}

void place_fruit(void) 
{
    char chr;
    int rx,ry;
    while (1) {
        rx = rand() % (maxx-1) + 1;
        ry = rand() % (maxy-1) + 1;
        chr = mvinch(ry,rx);
	    if (chr == ' ') break;
    }

    move(ry,rx);
    addch('O'|COLOR_PAIR(4));
//    mvprintw(ry,rx,"%c",79);
    refresh();
}