Memory leak concept in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a memory leak in C++?

A memory leak happens when a program allocates memory but never frees it, causing the memory to stay used and unavailable for other parts of the program or system.

beginner

Why are memory leaks a problem?

Memory leaks reduce the available memory over time, which can slow down or crash programs because they run out of memory to use.

intermediate

How do you prevent memory leaks in C++?

You prevent memory leaks by always freeing memory you allocate with 'delete' or 'delete[]' and by using smart pointers that automatically manage memory.

beginner

What is an example of a memory leak in C++?

If you use 'new' to create an object but never use 'delete' to free it, the memory stays allocated and causes a leak.

intermediate

What tools can help detect memory leaks in C++?

Tools like Valgrind or AddressSanitizer can find memory leaks by tracking allocated memory and checking if it is properly freed.

What causes a memory leak in C++?

A Writing to a file

B Using variables inside functions

C Allocating memory with 'new' and not freeing it with 'delete'

D Declaring too many variables

Memory leaks happen when allocated memory is not freed, like using 'new' without 'delete'.

Which C++ feature helps automatically manage memory and avoid leaks?

A Global variables

B Smart pointers

C Macros

D Inline functions

Smart pointers automatically free memory when no longer needed, preventing leaks.

What happens if a program has a memory leak?

A It runs faster

B It reduces CPU usage

C It frees memory automatically

D It uses more memory over time and may crash

Memory leaks cause programs to use more memory and can lead to crashes.

Which tool can help find memory leaks in C++ programs?

A Valgrind

B GCC compiler

C Git

D Makefile

Valgrind detects memory leaks by monitoring memory allocation and freeing.

What must you do after using 'new' in C++ to avoid leaks?

A Use 'delete' to free the memory

B Use 'malloc' instead

C Do nothing, memory frees automatically

D Use 'cout' to print the memory

You must use 'delete' to free memory allocated with 'new' to avoid leaks.

Explain what a memory leak is and why it is important to avoid it in C++ programs.

Think about what happens when memory is allocated but never freed.

Describe how smart pointers help prevent memory leaks in C++.

Smart pointers act like helpers that clean up memory for you.