Misc

Question: What is a wild pointer in a program? Uninitialized pointers are known as wild pointers. These are called so because they point to some arbitrary memory location and may cause a program to crash or behave badly. This can be understood from the below examples. Please note that if a pointer p points to a known variable then it’s not a wild pointer. In the below program, p is a wild pointer till this points to a. If we want pointer to a value (or set of values) without …

Question:What is a memory leak in a program? We have been writing many programs where we have used the “free()” keyword. One such example can be found in the “Delete the complete list” function found in the post – Important traversals in a Linked List. The code snippet is:- This is done due to a reason. When we allocate a memory in a program, usually that memory is unallocated once the execution of the program finishes. However, there may be some cases where the program runs forever and these scenarios, …

ITERATIVE VERSION The iterative version can be done in this way:- Input: num Initialize rev_num = 0 Loop while num > 0 Multiply rev_num by 10 and add remainder of num divide by 10 to rev_num rev_num = rev_num*10 + num%10; Divide num by 10 Return rev_num Here is an implementation of the same. RECURSIVE WAY

We will discuss how to calculate the result when a number ‘x’ is raised to the power ‘y’. Originally C provides a standard function that allows us to directly use the power function. It can be used in the following manner. Now suppose that we need to write a custom function by ourselves. Here are the sample methods by which we can do so. Simple Iterative method Recursive Method But in both these methods, the time complexity is of O(n), and this can take a long time in operation. We …

Here is an implementation of a simple algorithm that can be used to convert any number in decimal format to a number to any other base ‘b’. The base ‘b’ can be octal, binary or even any other arbitrary base like 7.

Question: Give an algorithm to reverse a queue. You can only use generic functions of the Queue ADT. Input: 4, 8, 15, 16, 23, 42 Output: 42,23,16,15,8,4 To solve this question will take the help of an auxiliary stack. The steps involved will be:- Create an auxiliary stack S. Until the queue Q is not empty, push the elements of the queue, in the stack S. Now we have a stack in which the last element of the Queue is at the TOP. Until the stack is empty POP(S) and …

Before implementing a queue, we must know the basic operations that should be available for a queue. Main Queue Operations:- enQueue(int data) :- Inserts an element at the end of the queue. int deQueue():- Removes and returns the element at the front of the queue. Auxiliary Queue Operations:- int front():- Returns the first element at the queue, without removing it. int queueSize():- Returns the size of the queue. int isEmptyQueue():- Indicates whether no elements are present. We can implement a queue using an ADT (Abstract Data Type). To implement a …

Question: You are given a stack and you have to reverse it, using only stack operations push and pop. The algorithm for the above problem can be given in this way:- First POP all elements of the stack till it becomes empty Now for each upward step in the recursion, push the elements at the bottom of the stack.

Suppose we want to find the minimum element available in a stack at any point of time. The most trivial and common method would be to traverse the entire stack and keep a record of the least element encountered. At the end, we can return this element. This method no doubt is easy, but it consists of traversing the entire stack again and again, which can lead to time complexities. Thus, we need to optimize it, and it can be done with a very neat little trick:- ALGORITHM:- Take an …

In infix expressions, the operator precedence is implicit unless we use parentheses. Therefore, for the infix to postfix conversion algorithm, we have to define the operator precedence inside the algorithm. We did this in the post covering infix, postfix and prefix expressions. What are infix, prefix and postfix expressions? Important properties:- Let us consider the infix expression 2 + 3 * 4 and its postfix will be 2 3 4 * +. Notice that between infix and postfix the order of the numbers(or operands) is unchanged. It is 2 3 …