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();
}

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

/*
 * Auther: Jayarathina Madharasan. Y
 * Website: http://www.madharasan.com/
 * Date: Oct, 10, 2008
 * This program performs animation of first fit, best fit, worst fit operating system concepts.
*/

#include<stdio.h>
#include<conio.h>
#define maxmem_no 100

int mem[maxmem_no], maxmem = maxmem_no;

void initmem()
{
int i = 0;
for(; i<maxmem; i++)
mem[i] = 0;
}

void comp()
{
int mem_temp[maxmem_no], i = 0, k;
for(; i<maxmem; i++)
mem_temp[i] = mem[i];
initmem();
for(i=0, k=0; i<maxmem; i++)
if(mem_temp[i] != 0)
{
mem[k] = mem_temp[i];
k++;
}
}

void removejob()
{
int jn, i=0;
printf("\nEnter Job Number to remove: "); scanf("%d", &jn);
if(jn<0)
{
printf("Error!");
getch();
return;
}
for (; i<maxmem; i++)
if (mem[i]== jn)
mem[i] =0;
}

void printmem()
{
int i =0;
for (printf("\n"); i<maxmem; i++)
{
(mem[i]==0)?printf("%c ", 176):printf("%c ", 219);
}
printf("\n\n");

for (i=0; i<maxmem; i++)
{
if(mem[i]!=0)
printf("%d ", mem[i]);
else
printf("  ");
}
printf("\n\n");
}

void memalloc(int jn, int jm, int mem_srt)
{
int i = mem_srt;
for(; i<=mem_srt+jm-1; i++)
mem[i] = jn;
}

int memfreeFF(int memreq)
{
int i=0, start = -1, end = -1;
calc:
start=-1, end=-1;
for(; i<maxmem; i++)
{
if(mem[i] == 0)
{
start = i;
break;
}
}
for(; i<maxmem; i++)
{
if(mem[i]==0)
{
end = i;
}
else
{
break;
}
}
if ((end - start +1) >= memreq)
{
return start;
}
else if(i<maxmem)
{
goto calc;
}
return -1;
}

int memfreeBF(int memreq)
{
int i=0, start = -1, end = -1;
int start_temp = -1, tot_free = -1;
calc:
start=-1, end=-1;
for(; i<maxmem; i++)
{
if(mem[i] == 0)
{
start = i;
break;
}
}
for(; i<maxmem; i++)
{
if(mem[i]==0)
{
end = i;
}
else
{
break;
}
}
if ((end - start +1) >= memreq)
{
if (start_temp != -1)
{
if(tot_free <= (end - start + 1))
{
start = -1; end = -1;
}
else
{
start_temp = start;
tot_free = end - start + 1;
start = -1; end = -1;
}
}
else{
start_temp = start;
tot_free = end - start + 1;
start = -1; end = -1;
}
}
if(i<maxmem)
{
goto calc;
}
return start_temp;
}


int memfreeWF(int memreq)
{
int i=0, start = -1, end = -1;
int start_temp = -1, tot_free = -1;
calc:
start=-1, end=-1;
for(; i<maxmem; i++)
{
if(mem[i] == 0)
{
start = i;
break;
}
}
for(; i<maxmem; i++)
{
if(mem[i]==0)
{
end = i;
}
else
{
break;
}
}
if ((end - start +1) >= memreq)
{
if (start_temp != -1)
{
if(tot_free >= (end - start + 1))
{
start = -1; end = -1;
}
else
{
start_temp = start;
tot_free = end - start + 1;
start = -1; end = -1;
}
}
else{
start_temp = start;
tot_free = end - start + 1;
start = -1; end = -1;
}
}
if(i<maxmem)
{
goto calc;
}
return start_temp;
}

int checkname(int num)
{
int i;
for(i=0;i<maxmem;i++)
if(mem[i] == num)
return 1;
return 0;
}

void fit(int cho)
{
int ch, jn, jm, temp;
char fnam [5][25] = {"First Fit", "Best Fit", "Worst Fit"};
clrscr();
printf("Enter Total Memory Size: ");
scanf("%d", &maxmem);
do{
clrscr();
printmem(); fflush(stdin);
printf("%s :\n\n1. Enter Job\n2. Remove Job\n3. Compaction\n4. Back\nEnter Your Choise: ", fnam[cho-1]);
scanf("%d", &ch);
switch(ch)
{
case 1:
printf("\nEnter Job Number: "); scanf("%d", &jn);
if((jn<0) || (checkname(jn) == 1))
{
printf("Error, Please enter a valid number!");
getch();
break;
}
printf("Enter required memory: "); scanf("%d", &jm);

switch(cho)
{
case 1:
temp = memfreeFF(jm); break;
case 2:
temp = memfreeBF(jm); break;
case 3:
temp = memfreeWF(jm); break;
}
if(temp == -1)
{
printf("\nInsufficient Memory!\n");
getch();
}
else
memalloc(jn, jm, temp);
break;
case 2:
removejob();
break;
case 3:
comp();
break;
case 4:
return;
default:
printf("Wrong Choise");
getch();
break;
}
}while(ch !=4);
getch();
}

void main()
{
int ch=0;
initmem();
do{
initmem();
fflush(stdin); clrscr();
printf("\nMenu\n");
printf("\n1. First Fit\n2. Best Fit\n3. Worst Fit\n4. Exit\n");
printf("\nEnter Your Choice: ");
scanf("%d", &ch);
if ( (ch > 4) || (ch <1) )
printf("Wrong Choise!\n Enter Again : ");
else if (ch != 4)
fit(ch);
else
{
printf("Thanks!");
break;
}
}while(ch != 4);
getch();
}