Converting strings to numbers is a fundamental task in C — every value read from scanf, fgets, or command-line arguments arrives as a string and must be explicitly converted. The standard library in <stdlib.h> provides three simple conversion functions: atoi() (string to int), atol() (string to long), and atof() (string to double/float). For robust error …
Command line arguments let users pass data to a C program at the moment they run it — without embedding values in the source code or prompting for input. When you run ./copy src.txt dst.txt, the strings src.txt and dst.txt arrive in your program through two special parameters: argc and argv. Understanding them is essential …
Pascal’s Triangle is a triangular array where each number is the sum of the two numbers directly above it. Row n, column k holds the binomial coefficient C(n,k) — the number of ways to choose k items from n. It appears in combinatorics, probability, the binomial theorem, and polynomial expansion. The C program below builds …
Floyd’s triangle in C is a right-angled triangular arrangement of consecutive natural numbers. Row 1 contains 1 number, row 2 contains 2, row 3 contains 3, and so on. It is named after Robert W. Floyd, who used it to teach loop control and nested iteration. The total numbers through row n is 1 + …
Measuring program execution time in C helps you benchmark algorithms and quantify how long different approaches take. The standard tool is the clock() function from <time.h>, which measures CPU time consumed by the program — not wall-clock time. Two snapshots (before and after) divided by CLOCKS_PER_SEC give you the elapsed time in seconds. clock() and …
Shell sort is a generalization of insertion sort that sorts elements far apart before sorting adjacent ones. Invented by Donald Shell in 1959, it repeatedly applies insertion sort on sublists of decreasing “gap” sizes until the gap reaches 1 — at which point one final insertion sort on the nearly-sorted array runs in near-linear time. …