Dynamic Programming

Question 1

Memory in C

Answer 1

Divided into 5 segments

1. Uninitialized data
2. Initialized data
3. Heap
4. Stack
5. Code

Question 2

Stack

Answer 2

Used to store automatics and activation records for functions
-located at the top of writable memory (grows downwards)

Question 3

Heap

Answer 3

Stores explicitly requested memory which must be dynamically allocated (grows upwards)

Question 4

Stack frame

Answer 4

Every time a function call is made a new stack frame is created and memory allocated for variables to be used by the function
- if stack and heap continue to grow, all memory available to the process will be exhausted and out of memory error will occur

Question 5

Reason for dynamic memory

Answer 5

If we don’t know how much memory will be used.

Then it would be inefficient to allocate as much memory as possible

Question 6

Heap memory

Answer 6

For dynamic allocation when size of not known until run-time

- malloc()

Question 7

Stack memory

Answer 7

When size is known at compile time

Question 8

Anonymous variables

Answer 8

Memory addresses in the heap, do not have names

Question 9

Malloc()

Answer 9

• allocate dynamic memory
• returns memory addresses and takes number of bytes of heap memory to be allocated
• must always check the value returned by malloc()
• have to use typecasting with malloc()
• need #include

Question 10

Free()

Answer 10

• use to return heap memory no longer needed back to the heap pool
• takes a pointer to the allocated block of memory

Question 11

Memory leaks

Answer 11

• occurs when heap memory is constantly allocated but is not freed
• systems with automatic garbage collection almost never have memory leaks but it is not in the control of the programmer