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How to use alloc's memory allocation functions?

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Join Date: Jun 2004

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How to use alloc's memory allocation functions?

Jun 18th, 2004

I have a very important question (for me)

How do i use <alloc.h>/<malloc.h>/<stdlib.h> for memory allocation?

i'm talking about: malloc(),calloc(),halloc(),realloc(),alloca(),heapwalk(),free()
etc?
i'm having a lot of trouble with these!

thank you!!

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Join Date: May 2004

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Re: How to use alloc's memory allocation functions?

Jun 19th, 2004

These are used to allocate memory dynamically.With these you get memory from the OS and point to that memory address with a pointer.

Presonally I use C++ new operator.

Eg.

Some_data_type *object;

object = (Some_data_type*)malloc(sizeof(Some_data_type),1);

that is to assign memory.

Then when you are finished with it:

free(object);

That's the general way to use it.

See what you can, remember what you need

Fourzon | Earn via Coding

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Join Date: Jun 2004

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Re: How to use alloc's memory allocation functions?

Jun 23rd, 2004

Thx. I looked it up in a book.

BTW: Instead of using a vector: int a[100] you could use:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
int *a;
a=(int*)malloc(100*sizeof(int)); OR
a=(int*)calloc(100,sizeof(int));
int *a;
a=(int*)malloc(100*sizeof(int)); OR
a=(int*)calloc(100,sizeof(int));

It's kind of useful. If you wanna read a vector of an undefined size (n), you have to aproximate and think within which intervals it is. If you use:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
int n;
//reads the size
printf("n=");
scanf("%i",&n);
int *a=(int*)malloc(n*sizeof(int));
int n;
//reads the size
printf("n=");
scanf("%i",&n);
int *a=(int*)malloc(n*sizeof(int));