Pointers

Pointers and Allocatable Arrays

Understand Fortran's two mechanisms for dynamic memory, the ALLOCATABLE attribute for owned, automatically-managed arrays, and POINTER for aliasing and flexibl…

Dynamic Memory Management

Understand pointers, the heap, and how to allocate, use, and free dynamic memory safely in Pascal.

Pointers in Pascal

Understand Pascal pointers, dynamic memory allocation with New/Dispose, and how they power dynamic structures like linked lists.

Delegates and Closures

Understand D's delegate type, how closures capture context, and how delegates power callbacks and higher-order functions.

Pointers and Indirection

How addresses, dereferencing, pointer arithmetic, LEA, and multiple levels of indirection work at the machine level in x86-64 assembly.

Dangling Pointers in C++

Understand how a pointer becomes 'dangling' after its target is freed or goes out of scope, and the safe practices that prevent it.

Null Pointers in C++

Learn what a null pointer is, why modern C++ prefers `nullptr` over the old `NULL` macro, and why dereferencing one causes undefined behavior.

Pointers and Arrays in C++

See how an array name decays into a pointer to its first element, and how `arr[i]` and `*(arr + i)` are two ways of writing the same thing.

Pointers and Functions in C++

Learn how passing a pointer to a function lets it modify the caller's original variable, unlike ordinary pass-by-value arguments.

Pointers in C++

Learn what a pointer is, how to declare one, and how the `&` and `*` operators let you access and manipulate memory addresses directly.

Pointers in C

Learn C pointers with syntax, address-of and dereference operators, pointer arithmetic, and common pitfalls, with examples and output.

Pointers in Go

A variable that holds the memory address of another value, enabling shared access and mutation without copying.

What is a Doubly Linked List?

A doubly linked list is a sequence of nodes where each node stores a value plus pointers to both the next and the previous node, allowing traversal in either d…

How Do You Detect a Cycle in a Linked List?

You detect a cycle in a linked list by walking it with two pointers moving at different speeds — a slow pointer advancing one node at a time and a fast pointer…

What is Floyd’s Cycle Detection Algorithm?

Floyd’s cycle detection algorithm, also called the tortoise-and-hare algorithm, finds whether a linked structure contains a cycle and, with a second phase, loc…

How Do You Find the Middle of a Linked List?

You find the middle of a linked list in a single pass using the slow-fast pointer technique: advance a slow pointer one node at a time and a fast pointer two n…

How Do You Clone a Linked List with a Random Pointer?

You clone a linked list where each node has both a next pointer and a random pointer (which may point anywhere in the list or to null) by first mapping every o…

How Do You Flatten a Multilevel Linked List?

You flatten a multilevel doubly linked list, where nodes can have a child pointer to a separate sublist in addition to next and prev, by depth-first traversal:…