Hello World in c

FIRST PROGRAM IN C

In this tutorial, We will write our first C program and understand the program structure in c. We will also see how to compile and run a C program.

Introduction

In this section, we will write our first program that will print Hello World on the terminal.

Create File/Open Editor

Create a file with name hello_world.c. Note that you can keep the name of file anything, but it is best practice to keep the name that related to the content of the file. C program file extension is .c means you can replace hello_world with any string but .c is compulsory. 

Write Hello World in C

Type below code in your hello_world.c file

#include <stdio.h>
int main()
{
   printf("Hello World");
   return 0;
}

How C Program Work

•  #include <stdio.h>: This is a preprocessor command which tells the compiler to include the contents of stdio.h file in the program. stdio.h file contains functions such as printf() to display output. So if you won't write  #include <stdio.h> in hello_word.c printf() function will not available in hello_word.c
• main(): Every C program contains the main function, program execution start from here. We will learn about function in the upcoming post. int is the return type of this function means main() function will return an integer
• printf(): printf() is another function which is written in stdio.h file. printf() used to display output on the terminal.
• return 0: Because our main function return type is an integer so we are returning 0 (an integer)

Compile and Run C Program

Open your terminal.
Make sure that hello_world.c file is in Home folder. If hello_world.c is not in Home folder either you can copy it to Home folder or cd to the folder which contains hello_world.c
Compile C program
Type below command on the terminal and hit enter key. It will compile your code and generate an object file with name hello_world that you have mentioned after -o

gcc -o hello_world hello_world.c

Here hello_world is binary file that we want to create and hello_world.c is our program file. So above command will create an binary file with name hello_world.

Run C program

Type below command on the terminal and hit enter key.

gcc ./hello_world

Here Hello_World is the binay file that is the output of compilation. 
Output

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

Plesae Solve these problem before moving to next section.
Practice Problem



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