Dynamic memory allocation (heap) in Compiler Design - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is dynamic memory allocation in the context of the heap?

Dynamic memory allocation is the process where a program requests memory from the heap at runtime, allowing flexible use of memory based on current needs.

beginner

Why is the heap used for dynamic memory allocation instead of the stack?

The heap allows allocating memory of variable size and lifetime, unlike the stack which is limited to fixed-size, short-lived data tied to function calls.

intermediate

What happens if a program requests more heap memory than is available?

The allocation fails, often causing the program to crash or return a null pointer, indicating no memory could be assigned.

intermediate

How does a compiler or runtime system manage heap memory?

It keeps track of allocated and free blocks, often using data structures like free lists, and handles requests to allocate or free memory dynamically.

beginner

What is a memory leak in the context of heap allocation?

A memory leak occurs when allocated heap memory is not freed after use, causing wasted memory and possible program slowdown or crash.

What is the main characteristic of heap memory?

A Memory that cannot be freed during program execution

B Memory allocated automatically for function calls

C Memory that stores only global variables

D Memory allocated at runtime with flexible size and lifetime

Heap memory is allocated dynamically at runtime and can have variable size and lifetime.

Which of the following is a common problem caused by improper heap memory management?

A Memory leak

B Syntax error

C Stack overflow

D Compilation failure

Memory leaks happen when heap memory is allocated but not freed properly.

When does dynamic memory allocation typically occur?

A Only during compilation

B Before program starts

C During program execution

D After program ends

Dynamic memory allocation happens while the program is running, not before or after.

What does the heap manager do?

A Tracks free and used memory blocks on the heap

B Manages CPU registers

C Allocates memory on the stack

D Compiles source code

The heap manager keeps track of which parts of the heap are free or used to handle allocation requests.

Which memory area is best suited for variables with unknown size at compile time?

A Code segment

B Heap

C Stack

D Data segment

The heap allows allocating memory dynamically for variables whose size is not known before running the program.

Explain what dynamic memory allocation on the heap is and why it is important in programming.

Think about how programs handle data when they don't know the size in advance.

Describe common issues that can arise from improper use of heap memory and how they affect a program.

Consider what happens if memory is not freed or if too much memory is requested.