Infix to postfix conversion in C transforms a human-readable arithmetic expression like A + B * C into postfix notation A B C * +, where operators follow their operands. Postfix eliminates the need for parentheses and precedence rules during evaluation — a stack scan from left to right is all that’s needed. This page …
An IPv4 address is displayed as four decimal octets separated by dots (e.g., 192.168.1.1) but is stored internally as a single 32-bit unsigned integer. Converting between the dotted-decimal string and the integer form is a fundamental networking operation — inet_addr() in the POSIX socket API does exactly this. Understanding how to do it manually shows …
This C program compares two strings and reports whether they are equal, or which one comes first in dictionary (lexicographic) order. Comparison works character by character: walk both strings together until two characters differ or a string ends, then decide from that first difference. This page shows a manual character-by-character implementation and the standard library …
The time.h library in C provides functions for getting the current date and time, formatting it for display, and converting between representations. The central type is time_t — typically a 32-bit or 64-bit integer counting seconds since the Unix epoch (1970-01-01 00:00:00 UTC). Five key functions cover the most common time operations: time(), ctime(), localtime(), …
The goto statement in C is an unconditional jump that transfers program control directly to a labelled statement within the same function. While modern C style discourages it, goto is still useful in a few real situations — most commonly for breaking out of deeply nested loops and for centralised cleanup/error handling. In this tutorial …
Variable scope controls where in a program a variable can be accessed. In C, a variable’s scope is determined by where it is declared: variables declared outside all functions have file scope (global), while variables declared inside a function or block have block scope (local). A third kind — static local variables — persist between …