Basic Structure of a C Program

A standard C program is divided into the following sections:

1. Documentation Section: (Optional) Comments explaining what the program does using // or /* ... */.
2. Preprocessor Directives: Commands like #include <stdio.h> that tell the compiler to link standard library files before compiling.
3. Global Declarations: (Optional) Variables declared outside all functions that can be used anywhere in the program.
4. The main() Function: The absolute starting point of every C program. Execution always begins here.
5. Subprograms (User-Defined Functions): (Optional) Other functions called by the main function.

// 1. Documentation: My First C Program

#include <stdio.h>  // 2. Preprocessor Directive

int globalVar = 10; // 3. Global Declaration

int main() {        // 4. Main Function
    printf("Hello, World!\n");
    return 0;
}

• #include <stdio.h>: Stands for Standard Input Output. It contains functions like printf() and scanf().
• { } (Curly Braces): These define the start and end of a block of code (the body of the function).
• ; (Semicolon): Every single statement in C must end with a semicolon. It is like a full stop in English.
• return 0;: Tells the operating system that the program has finished executing successfully.