How do you write a c code for memory allocation algorithms?

Answer 1

#include<stdio.h>

typedef struct hole

{

int id,size,inf,ef,filled,pid,psize;

}hole;

typedef struct process

{

int id,size,comp;

}process;

hole h[50];

process p[50];

int m,n,intfrag,exfrag;

void output()

{

int i;

intfrag=exfrag=0;

printf("\n\n\nHole Process IF EF\n");

for(i=0;i<m;i++)

{

printf("\n%d %d %d %d",h[i].size,h[i].psize,h[i].inf,h[i].ef);

intfrag=intfrag+h[i].inf;

exfrag=exfrag+h[i].ef;

}

}

void final()

{

int i;

for(i=0;i<n;i++)

{

if(p[i].comp==0)

{

printf("There is no memory for the process of size %d\n",p[i].size);

}

}

}

void input()

{

int i,max,flag;

max=flag=0;

printf("\nEnter total no of holes:\n");

scanf("%d",&m);

for(i=0;i<m;i++)

{

h[i].id=i;

printf("\nEnter size of hole %d:\n",i+1);

scanf("%d",&h[i].size);

h[i].inf=0;

h[i].ef=h[i].size;

h[i].filled=0;

h[i].pid=0;

h[i].psize=0;

}

for(i=0;i<m;i++)

{

if(h[i].size<0)

{

printf("\nInvalid input as hole size is negative");

flag=1;

}

if(h[i].size>max)

{

max=h[i].size;

}

}

printf("\nEnter total no of processes:\n");

scanf("%d",&n);

for(i=0;i<n;i++)

{

p[i].id=i;

printf("\nEnter size of process %d:\n",i+1);

scanf("%d",&p[i].size);

p[i].comp=0;

}

for(i=0;i<n;i++)

{

if(p[i].size<0)

{

printf("\nInvalid input as process size is negative");

flag=1;

}

if(p[i].size>max)

{

printf("\nInvalid input as process size is greater than max size of hole\n");

flag=1;

}

}

if(flag==0)

{

output();

}

}

void first()

{

int i,j;

for(i=0;i<n;i++)

{

for(j=0;j<m;j++)

{

if(p[i].size<=h[j].size && p[i].comp==0 && h[j].filled==0)

{

p[i].comp=1;

h[j].filled=1;

h[j].psize=p[i].size;

h[j].id=p[i].id;

h[j].inf=h[j].size-p[i].size;

h[j].ef=0;

output();

}

}

}

printf("\n\n\nInternal Fragmentation:%d",intfrag);

printf("\n\n\nExternal Fragmentation:%d\n\n",exfrag);

final();

}

void best()

{

int min,i,j,sub,var;

for(i=0;i<n;i++)

{

min=999;

sub=0;

for(j=0;j<m;j++)

{

if(p[i].size<=h[j].size && p[i].comp==0 && h[j].filled==0)

{

sub=h[j].size-p[i].size;

if(min>sub)

{

min=sub;

var=j;

}

}

}

p[i].comp=1;

h[var].filled=1;

h[var].psize=p[i].size;

h[var].id=p[i].id;

h[var].inf=h[var].size-p[i].size;

h[var].ef=0;

output();

}

printf("\n\n\nInternal Fragmentation:%d",intfrag);

printf("\n\n\nExternal Fragmentation:%d\n\n",exfrag);

final();

}

void next()

{

int i,j,a;

a=j=0;

for(i=0;i<n;i++)

{

for(j=a;j<m;j++)

{

if(p[i].size<=h[j].size && p[i].comp==0 && h[j].filled==0)

{

p[i].comp=1;

h[j].filled=1;

h[j].psize=p[i].size;

h[j].id=p[i].id;

h[j].inf=h[j].size-p[i].size;

h[j].ef=0;

output();

a=(j+1)%m;

}

}

}

printf("\n\n\nInternal Fragmentation:%d",intfrag);

printf("\n\n\nExternal Fragmentation:%d\n\n",exfrag);

final();

}

void main()

{

int ch;

printf("\n\n\n**********MEMORY ALLOCATION**********\n\n");

printf("\n1.First Fit Algorithm\n2.Best Fit Algorithm\n3.Next Fit Algorithm");

printf("\nEnter your choice:\n");

scanf("%d",&ch);

switch(ch)

{

case 1: input();

first();

break;

case 2: input();

best();

break;

case 3: input();

next();

break;

}

}

Written by: Fabianski Benjamin