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Question: What is the difference between doing:         ptr = (char **) malloc (MAXELEMS * sizeof(char *)); or:         ptr = (char **) calloc (MAXELEMS, sizeof(char*)); When is it a good idea to use calloc and when to use malloc ? There are two differences:- Firstly it is in the number of arguments, malloc() takes a single argument (memory required in bytes), while calloc() needs two arguments. Secondly, malloc() does not initialize the memory allocated, while calloc() initializes the allocated memory to ZERO. calloc() allocates a memory area, the length …

Question: In C, what is an unsigned char used for? How is this different from a regular char? In C, there are three distinct character types: char signed char unsigned char If you are using character types for text, use the unqualified char: it is the type of character literals like ‘a’ or ‘0’. it is the type that makes up C strings like “abcde” It also works out as a number value, but it is unspecified whether that value is treated as signed or unsigned. Beware character comparisons through …

Question: In C, what is the difference between using ++i and i++, and which should be used in the incrementation block of a for loop ? i++ is known as Post Increment whereas ++i is called Pre Increment. ++i will increment the value of i, and then return the incremented value. i++ will increment the value of i, but return the original value that i held before being incremented. For a for loop, either works. ++i seems more common, perhaps because that is what is used in Dennis Ritchie. In …

Question: How can you divide a number by 3 without using *, /, +, – % operator? Input: 48 Output: 16 The method below implements the method using bit-wise operators. For example if your number is 10 then convert to binary 10 =>00001010 if 10 > 3 then shift the binary number 2 bits Now num will be 00000010 ie, 2 Now sum will be 2 num = (shift the number by 2 bits)+(number BITWISE AND 3) num = 2+2 Now the number will be 4 then, 4>3 => true …

Given a number ‘n’, how to check if n is a Fibonacci number. A simple way is to generate Fibonacci numbers until the generated number is greater than or equal to ‘n’. Following is an interesting property about Fibonacci numbers that can also be used to check if a given number is Fibonacci or not. A number is Fibonacci if and only if one or both of 5n2+4 or 5×2-4 is a perfect square (Source: Wikipedia). Following is a simple program based on this concept. Output:- 1 is a Fibonacci …

Question: Suppose you are given a Linked List as 45-> 123-> 87-> 11-> 53-> 24-> 412-> 22. And we have to find the nth node from the end. Input:- n = 3 Output:- 24 BRUTE FORCE APPROACH:- In this method, start with the first node and count how many nodes are there after that node. If the number of nodes are < n-1, then return saying, “fewer number of nodes in the list.” If the number of nodes are > n-1 then go to the next node. Continue this until …

We covered some of the basic operations on a Linked List in this post. Basic operations on a Linked List However, in order to create a functional Linked List, we need even more operations before we can proceed further. Some of these operations are:- Inserting a node in the beginning of the Linked List. Inserting a node in the middle of a List. Inserting at a certain position Inserting after a specific node. Deleting a node from the Linked List. Deleting the entire Linked List. Inserting a node in the …

Here are some of the basic operations on a singly Linked List. Creating a new List Adding new elements Traversing a List Printing a List Basic functions to perform the above techniques have been defined in the code below. Creating a new list A new Linked List creation means that we do not have any elements in the list and we want to start fresh. This means allocating space in the memory for a node and then inserting the data into it. Since only a single node is created, the …

Linked List is a data structure used to store collections of data where successive elements are connected by pointers. It is really helpful to perform faster and memory efficient operations. This post gives you an introduction to all that with a video explanation.

So if you supply n = 4 in the function what you get as the output is this. 0000 1000 0100 1100 0010 1010 0110 1110 0001 1001 0101 1101 0011 1011 0111 1111 You can download the code here.