C Introduction & First Program

Key Takeaway:C is a fast and powerful programming language created in 1972 that powers operating systems and hardware.

What Is It & Why Use It?

C is one of the most popular programming languages in the world. It was developed by Dennis Ritchie at Bell Labs. Because C is very close to computer hardware, programs written in C run extremely fast. Almost every modern language—including C++, Java, Python, and JavaScript—borrowed ideas from C.

C Compilation & Execution Pipeline

Interactive Diagram

Visual Architecture & Runtime Schematic

C Compilation & Execution Pipeline

Stage 01

Source Code (.c file)

Source Code (.c file) -> Human readable C code with functions & headers

Example Code

#include <stdio.h>

int main() {
    printf("Hello, World! Welcome to C.
");
    return 0;
}

Language: c

Code Line-by-Line Breakdown

#include <stdio.h>

Tells the computer to include the Standard Input Output library so we can use printf().

int main() {

The main function. Every C program begins executing right here.

printf("Hello, World!\n");

Prints text to the screen. \n moves the cursor to a new line.

return 0;

Ends the main function and tells the operating system that our program finished successfully.

}

Closes the main function.

Remember These Rules

C is case-sensitive: main is different from Main.

Every statement in C must end with a semicolon (;).

Execution always starts at the main() function.

Quick Test

Which function is the mandatory entry point for every C program?