Linked Lists and C Pointers

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Questions and Answers

What is the effect of changing the value of *p when p points to an integer i?

i's value is updated to the value of *p. (correct)

i's value remains unchanged.

*p changes i's value to 0.

*p becomes an independent variable.

What function is used to append one string to another in C?

strlen

strcat (correct)

strcmp

strcpy

What does the strcmp function return when the two strings being compared are identical?

A negative value

0 (correct)

A positive value

Which of the following statements correctly describes a pointer?

A pointer holds the memory address of a variable. Signup and view all the answers

What happens to a child process when the parent process crashes or closes?

The child process is automatically terminated. Signup and view all the answers

What kind of scope do external variables have when they are declared in a file?

File scope Signup and view all the answers

In the statement `q = p;`, what type of assignment is being performed?

Pointer assignment Signup and view all the answers

What is a key characteristic of a linked list compared to an array?

Dynamic size Signup and view all the answers

What is one limitation of dealing with strings in C compared to other data types?

Strings cannot be copied or compared directly using operators. Signup and view all the answers

What does the 'Next' refer to in a linked list?

A link to the next element Signup and view all the answers

Which of the following is a disadvantage of linked lists?

Random access not allowed Signup and view all the answers

Which operation is NOT typically supported by a linked list?

Insertion at the end Signup and view all the answers

What is the primary limitation when using arrays for data storage?

Fixed memory size Signup and view all the answers

What does the arrow operator (->) in C specifically allow you to do?

Access members of a structure using pointers Signup and view all the answers

Which of the following is NOT an advantage of linked lists over arrays?

Cache friendliness Signup and view all the answers

According to common operations, how is deletion performed in a linked list?

Based on a specific key Signup and view all the answers

Study Notes

Linked Lists

Linked lists are sequential data structures where elements are connected via links.
Each link contains a data field and a connection to the next link.
Linked lists are widely used, second only to arrays.
Linked lists offer advantages over arrays, including dynamic size and easier insertion/deletion of elements.

Drawbacks of Linked Lists

Random access is not allowed, requiring sequential traversal from the first node.
Extra memory is needed for each element to store the pointer.
Linked lists are not cache-friendly due to non-contiguous memory allocation.

Linked List Operations

Insertion: Adds an element at the beginning of the list.
Deletion: Removes an element at the beginning of the list.
Display: Presents the entire list.
Search: Locates an element based on a given key.
Delete: Removes an element using a specified key.

C Pointers and Structures

The arrow operator (->) in C is used to access members of a structure using pointers.
For example: (pointer_name)->(variable_name)
The arrow operator retrieves the value stored in variable_name within the structure pointed to by pointer_name.

Differentiating Dot (.) and Arrow (->) Operators

The dot (.) operator accesses members of a structure directly.
The arrow (->) operator is used to access members of a structure indirectly through a pointer.

External Variables in C

Static Storage Duration: External variables have a permanent storage location, retaining their value throughout the program execution.
File Scope: External variables are visible from their declaration point to the end of the enclosing file.

Pointer Basics

Each byte in memory has a unique address.
Addresses can be stored in special variables called pointers.
If a pointer p points to a variable i, then *p functions as an alias for i, holding the same value.
Modifying *p alters the value of i.
The asterisk (*) in a pointer declaration (int *p) signifies that p is a pointer to an integer.

Pointer Assignment and Operations

C allows pointer assignment between pointers of the same type.
Pointer assignment (q = p) copies the pointer itself.
Indirection (*q = *p) copies the value pointed to by the pointers.

Pointers and Arrays

Pointers can be used to access array elements.
&a[i] represents a pointer to the element at index i in array a.

Strings and Arrays

Strings in C are treated as arrays of characters.
They are subject to the limitations of arrays, including restrictions on copying and comparison using normal operators.

String Manipulation Functions

strcat Function: Appends the contents of string s2 to the end of s1.
Prototype: char *strcat(char *s1, const char *s2);
Returns a pointer to the resulting string s1.
strcmp Function: Compares strings s1 and s2 lexicographically.
Prototype: int strcmp(const char *s1, const char *s2);
Returns a value less than, equal to, or greater than 0 based on the comparison result.

Process Concepts

A process represents an instance of a computer program being executed, containing its code and activity.
Processes can be created and managed using the fork() function, a key process management tool in Unix-like operating systems.

Process Creation with fork()

fork() creates a copy of the parent process, called the child process.
Both processes share the same code, data, and resources initially.
The child process typically executes its code independently from its parent.
The parent process can control the child process's lifespan.
When the parent process terminates, the child process is also terminated.

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Description

This quiz covers key concepts of linked lists, including their structure, operations, and the use of pointers in C programming. You'll explore advantages and drawbacks of linked lists, as well as how to perform insertion, deletion, and search operations. Test your knowledge on this essential data structure used in programming.