Basics of C Programming

By: Unknown on 00:54

This article is designed to be a stand-alone introduction to C, even if you've never programmed before.  I recommend the C, for people who have never programmed before. Because C is simple programming language and understandable to anyone.So Let's Start...

Getting set up - finding a C compiler

The very first thing you need to do, before starting out in C, is to make sure that you have a compiler. What is a compiler? A compiler turns the program that you write into an executable that your computer can actually understand and run. It means that the program which you write is in human understandable language known as source code, but machine doe's not understand this language, machine understand only binary language 1, 0. Compiler is the system software which convert source code into executable file.
If you don't have Compiler don't worry you can download it from following link... 

Download C Compiler + IDE

Sample Program

#include <stdio.h>

main()
{
  clrscr();
  printf("Hello World");
  getch();
}

Intro to C

Every full C program begins inside a function called "main”.  A function is simply a collection of commands that do "something". The main function is always called when the program first executes. From main, we can call other functions, whether they be written by us or by others or use built-in language features. To access the standard functions that comes with your compiler, you need to include a header with the #include directive. What this does is effectively take everything in the header and paste it into y our program. Let's look at a working program :

Let's look at the elements of the program. The #include is a "preprocessor" directive that tells the compiler to put code from the header called “stdio.h” into our program before actually creating the executable. By including header files, you can gain access to many different functions--both the “printf” and “getchar” functions are included in “stdio.h”. The next important line is int main(). This line tells the compiler that there is a function named main, and that the function returns an integer, hence int. The "curly braces" ({ and }) signal the beginning and end of functions and other code blocks. If  you have programmed in Pascal, you will know them as BEGIN and END. Even if you haven't programmed in Pascal, this is a good w ay to think about their meaning. The “printf” function is the standard C w ay of displaying output on the screen. The quotes tell the compiler that you want to output the literal string as-is (almost). The '\n' sequence is actually treated as a single character that stands for a new line (we'll talk about this later in m ore detail); for the time being, just remember that there are a few sequences that, w hen they appear in a string literal, are actually not displayed literally by “printf” and that '\n'  is one of them . The actual effect of  '\n'  is to move the cursor on y our screen to the next line. Notice the semicolon: it tells the compiler that you're at the end of a com m and, such as a function call. You w ill see that the semicolon is used to end m any lines in C. The next com m and is  “getchar()”. This is another function call: it reads in a single character and waits for the user to hit enter before reading the character. This line is included because many compiler environments will open a new console window, run the program , and then close the window before you can see the output. This com m and keeps that window from closing because the program is not done yet because it waits for you to hit enter. Including that line gives you time to see the program run. Finally, at the end of the program, we return a value from main to the operating system by using the return statement. This return value is important as it can be used to tell the operating system whether our program succeeded or not. A return value of 0 means success.

The final brace closes off the function. You should try com piling this program and running it. You can cut and paste the code into a file, save it as a c file, and then com pile it. If you are using a com m and-line compiler, such as Borland C+ + 5.5, you should read the compiler instructions for information on how to com pile. Otherwise com piling and running should be as simple as clicking a button with y our mouse (perhaps the "build" or "run" button). You might start playing around with the “printf” function and get used to writing simple C programs.

Read More