Snake Game using C program

#include<stdlib.h>
#include<ctype.h>
#include<conio.h>
#include<stdio.h>
#include<time.h>
#include<dos.h>

#define ESC 27
#define UPARR 72
#define LEFTARR 75
#define DOWNARR 80
#define RIGHTARR 77
#define SAVE 60
#define LOAD 61

main()
{
void starting(void);
void make_xy(char **,char **);
void getrand(char *,char *,char *,char *,char *,int,char);
char getkey(char,char);
void savegame(char *,char *,int,char);
int loadgame(char *,char *,char *);
void win_message(void);

char

*x,*y,pos_x,pos_y,num,out=0,old_ch=0,ch=0,new_ch,new_x,new_y,old_nu

m=0;
int i,length=6;

starting();
make_xy(&x,&y);
getrand(&pos_x,&pos_y,&num,x,y,length,ch);

while(!out){
if((new_ch=getkey(old_ch,ch))==ESC)
out=2;
if(out)
break;
if(new_ch==SAVE)
savegame(x,y,length,old_ch);
else if(new_ch==LOAD){
length=loadgame(x,y,&ch);
getrand(&pos_x,&pos_y,&num,x,y,length,ch);
}
else
ch=new_ch;
new_x=x[0];
new_y=y[0];
if(ch==UPARR)
new_y=y[0]-1;
else if(ch==LEFTARR)
new_x=x[0]-1;
else if(ch==DOWNARR)
new_y=y[0]+1;
else if(ch==RIGHTARR)
new_x=x[0]+1;
old_ch=ch;
if((new_x<2)|(new_y<2)|(new_x>79)|(new_y>22))
out=1; /* HIGHEST POSSIBLE SCORE ÷ (78*21-6)*5 = 8160 ÷ 10,000 */
for(i=1;i<length-!old_num;i++) /* NOT "length": TAIL-END MAY MOVE

AWAY! */
if((new_x==x[i])&(new_y==y[i])){
out=1;
break;
}
if((pos_x==new_x)&(pos_y==new_y)){
old_num+=num;
/* x=(char *)realloc(x,(score+6)*sizeof(char));
y=(char *)realloc(y,(score+6)*sizeof(char)); */
/* if((x==0)|(y==0)) */ /* PROBLEM IS NOT HERE */
/* x=x;*//* SOMEHOW realloc ISN'T COPYING PROPERLY */
getrand(&pos_x,&pos_y,&num,x,y,length,ch);
}
if(!old_num){
gotoxy(x[length-1],y[length-1]);
putchar(' ');
}
else{
length++;
if(length==1638){
win_message();
return 0;
}
gotoxy(67,25);
printf("Score = %5d",length-6);
old_num--;
x[i+1]=x[i];
y[i+1]=y[i];
}
for(i=length-1;i>0;i--){
x[i]=x[i-1];
y[i]=y[i-1];
if(i==1){
gotoxy(x[i],y[i]);
putchar('Û');
}
}
x[0]=new_x;
y[0]=new_y;
gotoxy(x[0],y[0]);
printf(" \b"); /* USE THE FUNCTION _setcursortype() */
if(out)
break;
delay(99);
}
if(out==1){
gotoxy(1,24);
printf("The snake collided with the wall or with itself!\n"
"GAME OVER!!\t\t(Press 'q' to terminate...)");
gotoxy(x[0],y[0]);
while(toupper(getch())!='Q');
}
clrscr();
printf("Hope you enjoyed the game\n\n\t\tBye!\n");
return 0;
}

/*-------------------------------------------------------------------------*/

void starting()
{
char i;

clrscr(); /* FIRST TO DRAW A BOUNDARY for THE GAME */
putchar('É');
for(i=0;i<78;i++)
putchar('Í');
putchar('»');
gotoxy(1,23);
putchar('È');
for(i=0;i<78;i++)
putchar('Í');
putchar('¼');
window(1,2,1,23);
for(i=0;i<21;i++)
cprintf("º");
window(80,2,80,23);
for(i=0;i<21;i++)
cprintf("º"); /* THE BOUNDARY IS DRAWN */
window(1,1,80,25);
gotoxy(38,12);
printf("ÛÛÛÛÛ "); /* THE "SNAKE" IS PUT for THE FIRST TIME */
gotoxy(1,24);
printf("Welcome to the game of SNAKE!\n(Press any arrow key to start now,"
" Escape to leave at any time...)"); /* WELCOME MESSAGE */
gotoxy(43,12);
while(!kbhit());
gotoxy(30,24);
delline();delline(); /* REMOVING MESSAGE */
cprintf("\n( EAT THE NUMBER !! ) Score = 0");
gotoxy(43,12); /* GO TO THE HEAD OF THE SNAKE */
}

void make_xy(char **px,char **py)
{
char i;

*px=(char *)malloc(1638*sizeof(char)); /*EARLIER IT WAS 6, NOT 1638;

BUT*/
*py=(char *)malloc(1638*sizeof(char)); /*realloc IS NOT COPYING

PROPERLY*/
for(i=0;i<6;i++){
(*px)[i]=43-i;
(*py)[i]=12;
} /* THE TWO ARRAYS for COORDINATES OF THE SNAKE ARE

SIMULATED */
}

void getrand(char *px,char *py,char *pn,char *x,char *y,int length,char ch)
{
int allowed=0,i; /* i AND length MUST BE int */

while(!allowed){
allowed=1;
srand((unsigned)time(0));
*px=rand()%78+2; /* GENERATING RANDOM POSITIONAL

COORDINATES for */
srand((unsigned)time(0));
*py=rand()%21+2; /* PUTTING A RANDOM NUMBER */
if(ch==UPARR){
if((*px==x[0])&(*py==y[0]-1))
allowed=0;
}
else if(ch==DOWNARR){
if((*px==x[0])&(*py==y[0]+1))
allowed=0;
}
else if(ch==LEFTARR){
if((*px==x[0]-1)&(*py==y[0]))
allowed=0;
}
else if((ch==RIGHTARR)&(*px==x[0]+1)&(*py==y[0]))
allowed=0;
for(i=0;(i<length)&&allowed;i++)
if((*px==x[i])&(*py==y[i]))
allowed=0;
} /* THE RANDOM NUMBER GENERATED SHOULD NOT BE PUT

ON SNAKE'S BODY */
srand((unsigned)time(0));
*pn=rand()%9+1; /* THE NUMBER */
gotoxy(*px,*py);
putchar(*pn+48);
gotoxy(x[0],y[0]);
}

char getkey(char old_ch,char ch)
{
char i;

if(kbhit())
for(i=0;i<5;i++){ /* if i too low, takes too many keystrokes */
while((ch=getch())==0);
if(ch==27){
/* out=2;
i=5;
break;*/return ch;
}
if((ch!=LOAD)&(ch!=SAVE)&(ch!=UPARR)&(ch!=DOWNARR)&
(ch!=LEFTARR)&(ch!=RIGHTARR))
continue;
if((ch!=old_ch)|(!kbhit()))
break;
}
else
for(i=0;(i<12)&(!kbhit());i++)
delay(100);
return ch;
}

void savegame(char *px,char *py,int length,char ch)
{
FILE *fp;
int i;

rename("snake.sav","snake.bak");
fp=fopen("snake.sav","wb");
fprintf(fp,"%d %c",length,ch);
for(i=0;i<length;i++)
fprintf(fp,"%c%c",px[i],py[i]);
fclose(fp);
}

int loadgame(char *px,char *py,char *pch)
{
FILE *fp;
int length,i;

fp=fopen("snake.sav","rb");
if(!fp){
clrscr();
puts("ERROR: no saved game found in current directory!!!\n\n\t\t"
"Exiting...\n");
sleep(3);
exit(1);
}
window(2,2,79,22);
clrscr();
/* fscanf(fp,"%d %c ",&length,pch);*/
fscanf(fp,"%d %c",&length,pch);
for(i=0;i<length;i++){
/* fscanf(fp,"%d %d ",&px[length],&py[length]);*/
fscanf(fp,"%c%c",&px[i],&py[i]);
gotoxy(px[i]-1,py[i]-1);
putchar('Û');
}
window(1,1,80,25);
gotoxy(30,24);
delline();delline(); /* REMOVING MESSAGE */
cprintf("\n( EAT THE NUMBER !! ) Score = %5d",length-6);
gotoxy(px[0],py[0]);
printf(" \b");
fclose(fp);
return length;
}

void win_message()
{
window(1,1,80,25);
gotoxy(1,24);
delline();delline();
textcolor(14);
cprintf("CONGRATULATION!! YOU HAVE COMPLETED THE GAME!!

\r\n"
"(Press any key to terminate...)");
clrscr();
textcolor(7);
}