Memory Allocation

 

Memory Allocation in C

 it is a process by which a particular computer program is allocated memory space. There are two types of memory allocations. Static and dynamic.

Static Memory Allocation

When the allocation of memory performs at the compile time, then it is known as static memory. In this, the memory is allocated for variables by the compiler.

When the memory allocation is done at the execution or run time, then it is called dynamic memory allocation.

Static memory allocation is performed when the compiler compiles your program

Static memory allocation requires knowing the size of the data it needs before it starts running.

Array declaration is an example of static memory allocation. The size of the array must be known in advance. Arrays cannot be resized after memory has been allocated.

 Dynamic Memory Allocation

When the memory allocation is done at the execution or run time, then it is called dynamic memory allocation.

Memory is allocated to an instance of a program when it is first used during program execution. Since the actual size of the data required is known at run time, the program is allocated the correct amount of memory, reducing memory waste.

· malloc () − allocates a block of memory in bytes at runtime.

· calloc () − allocating non-stop blocks of memory at run time.

 Difference between Static & Dynamic Memory Allocation

Static Memory Allocation	Dynamic Memory Allocation
Static Memory Allocation memory is allocated at compile time.	Dynamic Memory Allocation memory is allocated at run time.
Memory cannot be Changed while executing a program.	memory can be Changed while executing a program.
Used in an array.	Used in the linked list.
It is fast and saves running time.	It is a bit slow.
It is less efficient than the Dynamic allocation strategy.	It is more efficient than the Static allocation strategy.
Example: Array int a [10];	Example: Pointer p = malloc(sizeof(int));

 

 

Dynamic Memory Allocation

• Dynamic Memory Allocation memory is allocated at runtime, once the memory is allocated, the memory size can be changed.

 

• There are 4 types of dynamic memory allocation functions
• malloc ()
• calloc()
• realloc()
• free ()

Function	Syntax
malloc ()	malloc (number *sizeof(int));
calloc ()	calloc (number, sizeof(int));
realloc ()	realloc (pointer_name, number * sizeof(int));
free ()	free (pointer_name);

 

• malloc () function in C

The malloc () function allocates single block for memory.

• calloc() function in C

The calloc() function allocates multiple block for memory.

• realloc() function in C

You can reallocate the memory by realloc() function.In other words it changes the memory size.

 

• free () function in C

The memory occupied by malloc() or calloc() functions must be released by calling free() function.

Difference between malloc () and calloc ()

S.No.	malloc()	calloc()
1.	malloc() function creates a single block of memory of a specific size.	calloc() function assigns multiple blocks of memory to a single variable.
2.	The number of arguments in malloc() is 1.	The number of arguments in calloc() is 2.
3.	malloc() is faster.	calloc() is slower.
4.	malloc () has high time efficiency.	calloc() has low time efficiency.
5.	The memory block allocated by malloc() has a garbage value.	The memory block allocated by calloc() is initialized by zero.
6.	malloc () indicates memory allocation.	calloc() indicates contiguous allocation.

 

 

 

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Milan Tomic

Hi. I’m Designer of Blog Magic. I’m CEO/Founder of ThemeXpose. I’m Creative Art Director, Web Designer, UI/UX Designer, Interaction Designer, Industrial Designer, Web Developer, Business Enthusiast, StartUp Enthusiast, Speaker, Writer and Photographer. Inspired to make things looks better.

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