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();
}