First C program, Hello World | ShreeSanaviAcademy Portal for Students

Introduction Generations of Computers Classification of Computers Basic Anatomy of a Computer System Memory Management Computer Software Operating System

Algorithm Flowcharts

Programming Language Generations of Programming Languages Introduction to C Structure of C Programming Language Integrated Development Environment First C program, Hello World Executing a C Program Constants in C Variables in C C Storage Classes and Storage Class Specifiers

Introduction Arithmetic operators Relational Operators Logical Operators Assignment Operator Increment and Decrement Operators Conditional Operators Bitwise Operators Precedence and Associativity

Control Instructions in C if Statement in C if-else Statement Nested if-else statement else if ladder Switch Statements in C

Loops Introduction for Loop while loop in C do-while Loop break and continue statements

Array in C One Dimensional array Two Dimensional Array Multidimensional Arrays

Modular Programming Functions

Searching Techniques Linear Search Algorithm Binary-Search-Algorithm

Sorting Introduction Bubble Sort

What is Strings Standard Library String Functions

Structure Introduction Defining a Structure Declaration of Structure Example of Structure Union Introduction Defining a Union Accessing Union Members

Pointers in C Accessing the Address of a variable Pointer Operations

Dynamic Memory Allocation

First C program, Hello World

#include<stdio.h>
	int main ()
	{
		printf(“Hello World\n”);
		return 0;
	}

#include<stdio.h>

We include a file called stdio.h (Standard Input/Output header file) with this line of code. This file allows us to use certain commands for input and output in our software. (Think of it as lines of code commands) that someone else has written for us. It features input commands like reading from the keyboard and output commands like printing items on the screen, for example.

int main()

The return value is represented by an int (in this case of the type integer). It will be described later on what it was used for. There must be a major character in every program (). It serves as the beginning point for all programs.

{ }

The two curly brackets (one in the beginning and one at the end) are used to group all commands together. In this case all the commands between the two curly brackets belong to main(). The curly brackets are often used in the C language to group commands together.

Printf(“Hello World\n”);

The printf is used for printing things on the screen, in this case, the words: Hello World. As you can see the data that is to be printed is put inside round brackets. The words Hello World are inside inverted commas, because they are what is called a string. (A single letter is called a character and a series of characters is called a string). Strings must always be put between inverted commas. The \n is called an escape sequence. In this case, it represents a newline character. After printing something to the screen you usually want to print something on the next line. If there is no \n then the next printf command will print the string on the same line.

Commonly used escape sequences are:

\n (newline)
\t (tab)
\v (vertical tab)
\f (new page)
\b (backspace)
\r (carriage return)

After the last round bracket there must be a semi-colon. The semi-colon shows that it is the end of the command. (So in the future, don’t forget to put a semi-colon if a command ended).

return 0;

When we wrote the first line “int main ()”, we declared that main must return an integer int main (). (int is short for integer which is another word for number). With the command return 0; we can return the value null to the operating system.

Fundamentals of the Computer System

Introduction to Algorithm

Programming Basics

Operators in C

Conditional Branching

Iteration and Loops

Array in C

Functions in C

Searching Algorithms

Sorting Algorithms

Strings

Structures and Union

Pointers in C

File Handling in C

Advanced

#include<stdio.h>

int main()

Printf(“Hello World\n”);

Commonly used escape sequences are:

return 0;