The full code

malloc.c

#include<stdio.h>
#include<stddef.h>
#include "mymalloc.h"


void initialize(){
freeList->size=20000-sizeof(struct block);
freeList->free=1;
freeList->next=NULL;
}

void split(struct block *fitting_slot,size_t size){
struct block *new=(void*)((void*)fitting_slot+size+sizeof(struct block));
new->size=(fitting_slot->size)-size-sizeof(struct block);
new->free=1;
new->next=fitting_slot->next;
fitting_slot->size=size;
fitting_slot->free=0;
fitting_slot->next=new;
}


void *MyMalloc(size_t noOfBytes){
struct block *curr,*prev;
void *result;
if(!(freeList->size)){
initialize();
printf("Memory initialized\n");
}
curr=freeList;
while((((curr->size)<noOfBytes)||((curr->free)==0))&&(curr->next!=NULL)){
prev=curr;
curr=curr->next;
printf("One block checked\n");
}
if((curr->size)==noOfBytes){
curr->free=0;
result=(void*)(++curr);
printf("Exact fitting block allocated\n");
return result;
}
else if((curr->size)>(noOfBytes+sizeof(struct block))){
split(curr,noOfBytes);
result=(void*)(++curr);
printf("Fitting block allocated with a split\n");
return result;
}
else{
result=NULL;
printf("Sorry. No sufficient memory to allocate\n");
return result;
}
}

void merge(){
struct block *curr,*prev;
curr=freeList;
while((curr->next)!=NULL){
if((curr->free) && (curr->next->free)){
curr->size+=(curr->next->size)+sizeof(struct block);
curr->next=curr->next->next;
}
prev=curr;
curr=curr->next;
}
}

void MyFree(void* ptr){
if(((void*)memory<=ptr)&&(ptr<=(void*)(memory+20000))){
struct block* curr=ptr;
--curr;
curr->free=1;
merge();
}
else printf("Please provide a valid pointer allocated by MyMalloc\n");
}

                                                                                                                                            

malloc.h


#include<stdio.h>
#include<stddef.h>

char memory[20000];

struct block{
size_t size;
int free;
struct block *next;
};

struct block *freeList=(void*)memory;

void initialize();
void split(struct block *fitting_slot,size_t size);
void *MyMalloc(size_t noOfBytes);
void merge();
void MyFree(void* ptr);

                                                                                                                                            

Main.c

#include<stdio.h>

int main(){

int *p=(int)MyMalloc(100*sizeof(int));

char *q=(char)MyMalloc(250*sizeof(char));

int *r=(int)MyMalloc(1000*sizeof(int));

MyFree(p);

char *w=(char)MyMalloc(700);

MyFree(r);

int *k=(int)MyMalloc(500*sizeof(int));

printf("Allocation and deallocation is done successfully!");

}