C Programming 07/8

Question 1

What is Static Allocation?

Answer 1

Storage allocated statically when program starts, freed automatically when program ends.
• Variable defined with the static identifier in functions.
• Both static and non-static variables at the global scope.

Question 2

What is Stack Allocation?

Answer 2

Memory automatically allocated when function is executed.
• Fixed size of memory automatically allocated at run- time.
• Used for variables that are local to a block

Question 3

What is Dynamic Allocation?

Answer 3

Memory allocated at run-time.
• Done manually by the programmer.
• Lifetime of the memory is handled by the programmer.

Question 4

What is malloc?

Answer 4

Allocates a new block of raw memory of certain size (in bytes)
• void *malloc(size_t size);
• Returns NULL if there is insufficient memory left in the OS.
• Memory returned has no type, and will be filled with random data

Question 5

What is free?

Answer 5

Returns a block of memory to the OS.
• void free(void *ptr);
• There is no automatic memory management
• Undefined behaviour if you read or write from a pointer into a block of already freed memory.