Memory Allocation; Static and Dynamic

[jimin-kiim]

• Object Creation
• Memory Leak
• Dangling pointer
• Pros and Cons of static and dynamic memory allocation

[jimin-kiim]

Object Creation

Static Way

classname objectname(arguments);

Dynamic Way

classname* objectname = new classname(arguments);
heavier and slower
so it should be done only when needed

[jimin-kiim]

Memory Leak

• when the dynamic allocation is done inside the function but the function is returned without deallocating the allocated memory
• the condition when the dynamically allocated memory cannot be accessed and deallocated anymore unless the program is terminated
• waste of memory; the memory is not useful anymore but still allocated
• if it's accumulated, the program just crahses
• in the case of Java, if there's a memory leak then the garbage collection handles it. The memory garbages are automatically collected and deallocated. So in Java, there's no deallocating

[jimin-kiim]

Dangling Pointer

• the pointer that points to the allocated memory that should have been deallocated but not.

[jimin-kiim]

Pros and Cons of static and dynamic memory allocation

sometimes the static memory allocation is more suitable and sometimes the dynamic memory allocation is more suitable. Understanding the pros and cons of each of them and using them in pertinent situation is necessary.

static memory allocation

• advantage :
  • light-weight.
  • faster to be created and deleted than dynamic allocating method
  • higher speed of the program in the execution time( since the memory allocation is already performed at the compile time. )
• disadvantage :
  • the exact size of the array must be specified when declaring the array

dynamic memory allocation

• advantage :
  • no need to specify the exact memory size ( even in the case when I cannot expect the size of array in advance, I can declare the array)
• disadvantage :
  • heavy-wight
  • slower speed of the program when executed( since the prodedure of allocating the memory is performed during the run time)

• When I have to make a fast program then it's better to use the static memory allocating method
• When I cannot expect the size of the array in advance of executing the program, it's better to use the dynamic memory allocating method