#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
The main advantage of dynamic memory allocation is flexibility: the sizes of structures (or upper bounds on the sizes) do not need to be known in advance, so any size input that does not exceed available memory is easily handled. There are costs, however. Repeated calls to allocate and de-allocate memory place considerable strain on the operating system and can result in "thrashing" and decreased performance. In addition, one has to be very careful to "clean up" and de-allocate any memory that is allocated dynamically, to avoid memory leaks. The general rule of thumb is, if you can allocate memory statically, do it, because the result will probably be faster code that is easier to debug. But if you need to handle wide-ranging input sizes, then dynamic memory allocation is the way to do it.
the number of steps of an algorithm will be countable and finite.
No. Indeed, algorithms are actually meant for humans, not computers. Computer programmers translate algorithms into working code such that a computer can process the algorithm. The code is actually the implementation of the algorithm, not the algorithm itself.
yes we can do it,in c
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The main advantage of dynamic memory allocation is flexibility: the sizes of structures (or upper bounds on the sizes) do not need to be known in advance, so any size input that does not exceed available memory is easily handled. There are costs, however. Repeated calls to allocate and de-allocate memory place considerable strain on the operating system and can result in "thrashing" and decreased performance. In addition, one has to be very careful to "clean up" and de-allocate any memory that is allocated dynamically, to avoid memory leaks. The general rule of thumb is, if you can allocate memory statically, do it, because the result will probably be faster code that is easier to debug. But if you need to handle wide-ranging input sizes, then dynamic memory allocation is the way to do it.
the number of steps of an algorithm will be countable and finite.
No. Indeed, algorithms are actually meant for humans, not computers. Computer programmers translate algorithms into working code such that a computer can process the algorithm. The code is actually the implementation of the algorithm, not the algorithm itself.
C++ has 4 distinct regions for memory distribution Stack : This region is used for function calls' return addresses , arguments and local variables Heap : This region is for dynamic allocation of memory (dynamic variables created on run time use this memory , aka RAM) Global Variables : This is used for global variables defined by the programmer Program Code : This region is for the program code.
A memory leak is when allocated memory that is no longer needed is not deallocated. Eventually, the memory pool is unable to satisfy an allocation request, and the program fails. A memory leak is a programming bug. When class libraries leak memory, they need to be fixed, just like any other piece of code that has bugs. If they came from a vendor, then that vendor needs to fix them.
Transaction Allocation and management
yes we can do it,in c
Memory management functions handle the allocation and deallocationof dynamic Memory. These functions form an abstraction layer above the standard C memory management functionsmalloc, free, and realloc.This block of functions can be replaced by the user with custom code to implement a different memory management scheme. For example, an embedded system application might want to use a fixed-sized static block from which to allocate.
Often an application needs additional memory for the temporary storage of data. For example, the C programming language allows the programmer to use the MALLOC (memory allocate) function to grab a chunk of memory suitable for the applications needs. Failure to release the memory after it is used by using the FREE function can result in problems. It is called dynamic memory allocation because the memory is allocated at run-time, as needed. Unlike variables created within functions - the memory is not allocated on the processor stack, instead, when using MALLOC or the 'new' keyword, memory is allocated in the applications virtual address space.
Allocate more memory to the stack or write code that does not leave stuff on the stack.
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int main (void) { puts ("File allocation methods"); return 0; }