Memory Management - First Fit, Best Fit and Worst Fit (Simple)

#include<stdio.h>
#include<conio.h>

struct memory
{
 int ind;
 int prn;
 int stpt;
 int space;
 struct memory *nxt;
}*start,*ptr,*ptrc,*loc,*locp,*np;

int ttl_space,rem_space;

int chk_avail(int num,int mem)
{
 if(mem > rem_space)
   return 0;
 else
 {
  ptr = start;
  while(ptr != NULL)
  {
   if(ptr->ind == 1 && ptr->prn == num)
    return 0;
   if(ptr->ind == 0 && ptr->space >= mem)
    return 1;
   ptr = ptr->nxt;
  }
  return 0;
 }
}

void getstats()
{
  ptr = start;
  printf("\n Process           Starting Point        Memory Allocated \n");
  printf(" ---------------------------------------------------------- \n");
  while(ptr != NULL)
  {
    if(ptr->ind == 1)
     printf("\n\t%d\t\t",ptr->prn);
    else
     printf("Free Space\t\t\n",ptr->prn);
    printf("%d\t\t\t%d\n",ptr->stpt,ptr->space);
   ptr = ptr->nxt;
  }
 printf("\n\t\t     Total Memory Space : %d",ttl_space);
 printf("\n\t\t Total Allocated Memory : %d",ttl_space-rem_space);
 printf("\n\t\t Total Available Memory : %d",rem_space);
}

void first_fit(int mem)
{
 loc = start;
 locp = NULL;
 while(loc != NULL)
 {
   if(loc->ind == 0 && loc->space >= mem)
    break;
   locp = loc;
   loc = loc->nxt;
 }
}

void best_fit(int mem)
{
 int small = ttl_space;
 loc = start;
 locp = NULL;
 while(loc != NULL)
 {
   if(loc->ind == 0 && loc->space >= mem && loc->space - mem  < small )
   {
    ptrc = locp;
    ptr = loc;
    small = loc->space - mem;
   }
   locp = loc;
   loc = loc->nxt;
 }
 locp = ptrc;
 loc = ptr;
}

void worst_fit(int mem)
{
 int big = 0;
 loc = start;
 locp = NULL;
 while(loc != NULL)
 {
   if(loc->ind == 0 && loc->space >= mem && loc->space - mem  > big )
   {
    ptrc = locp;
    ptr = loc;
    big = loc->space - mem;
   }
   locp = loc;
   loc = loc->nxt;
 }
 locp = ptrc;
 loc = ptr;
}

void allocate()
{
  int cho,res,nm,mm;
  do
  {
  printf("\n Enter process number : ");
  scanf("%d",&nm);
  printf("\n Enter memory space reqd. : ");
  scanf("%d",&mm);
  res = chk_avail(nm,mm);
  }while(res == 0);
  printf("\n Therefore, Process is unique and Reqd. Memory is availiable. ");
  printf("\n\n\t By which method you want to allocate Memory ?? ");
  printf("\n 1. First Fit\n 2. Best Fit\n 3. Worst Fit");
  printf("\n\n\t Choose your Option : ");
  scanf("%d",&cho);
  switch(cho)
  {
   case 1 : first_fit(mm); break;
   case 2 : best_fit(mm); break;
   case 3 : worst_fit(mm); break;
   default: printf("\n\n\t Try again later !! "); break;
  }
  if(cho>=1&&cho<=3)
  {
   np = new memory;
   np->ind = 1;
   np->prn = nm;
   np->stpt = loc->stpt;
   np->space = mm;
   np->nxt = NULL;
   if(loc == start)
   {
    np->nxt = start;
    start = np;
   }
   else
   {
    locp->nxt = np;
    np->nxt = loc;
   }
   if(loc->space != np->space)
   {
   loc->stpt = np->stpt + np->space;
   loc->space = loc->space - np->space;
   }
   else
   {
    np->nxt = loc->nxt;
    delete loc;
   }
   rem_space -= np->space;
   getstats();
  }
}

void deallocate()
{
  int res,nm;
  printf("\n Enter process number to be deallocated : ");
  scanf("%d",&nm);
  res = chk_avail(nm,ttl_space);
  if(res != 0)
   printf("\n\t\t Sorry !! Can't be deleted !!! \n");
  else
  {
   locp = NULL;
   loc = start;
   while(loc != NULL)
   {
    if(loc->ind == 1 && loc->prn == nm)
      break;
    locp = loc;
    loc = loc->nxt;
   }
   rem_space += loc->space;
   loc->ind = 0;
   locp = start;
   loc = start->nxt;
   while(loc != NULL)
   {
    if(locp->ind == 0 && loc->ind == 0 )
    {
     locp-> space += loc->space;
     locp->nxt = loc->nxt;
     delete loc;
     loc = locp->nxt;
    }
    else
    {
     locp = loc;
     loc = loc->nxt;
    }
   }
   printf("\n\t Therefore, The Given Memory Space has been deallocated \n");
   getstats();
  }
}

void main()
{
 int cho;
 do
 {
 clrscr();
 printf("\n Enter the maximum space in memory : ");
 scanf("%d",&ttl_space);
 }while(ttl_space<=0 || ttl_space >= 10000);
 rem_space = ttl_space;
 np = new memory;
 np->stpt = np->ind = 0;
 np->space = ttl_space;
 np->nxt = NULL;
 start = np;
 do
 {
  getch();
  clrscr();
  printf("\n\t What would you like to do now in ?? \n");
  printf("\n1. Allocate Memory by Inserting Process ");
  printf("\n2. Deallocate Memory by Removing Process ");
  printf("\n\n\t Choose your option : ");
  scanf("%d",&cho);
  switch(cho)
  {
   case 1 :  allocate();  break;
   case 2 :  deallocate(); break;
   default:  printf("\n\t\t Thanks for Using The Program \n");  break;
  }
 }while(cho>=1&&cho<=2);
 getch();
}