The factorial program in C is one of the most common exercises for learning recursion and loops. The factorial of a non-negative integer n, written n!, is the product of all positive integers from 1 to n. By definition, 0! = 1. This page covers two approaches — iterative and recursive — with compile-verified code, …
Very often we encounter a situation where we have to search for a given target value in a list of values. Simple value types like integers are stored in arrays. This program demonstrates how to do a search within an array by using a method called linear search. Linear search, also called as ‘Sequential search’ …
The getchar() function reads a single character from standard input (the keyboard) and returns it. It is one of the simplest input functions in C and a great way to understand how the input buffer works. In this program we use getchar() in a loop to read text entered by the user and count how …
Combinations and permutations in C are computed using two related formulas. A combination C(n, r) counts the number of ways to choose r items from n items where order does not matter. A permutation P(n, r) counts the number of ways to arrange r items chosen from n items where order matters. C(n, r) = …
C preprocessor directives are instructions that run before compilation. The preprocessor reads your source file, processes every line that starts with #, and hands the result to the compiler. Understanding them well means smaller code, safer constants, conditional compilation for different platforms, and header files that include safely more than once. Object-Like Macros — #define …
The ctype.h header provides a set of functions for testing and converting individual characters. Each function takes an int (the ASCII value of a character) and returns a non-zero value (true) if the character belongs to a certain class. They are used in parsers, tokenizers, input validation, and any code that processes text character by …