There is no one in this world who is born as a programmer .To write efficient programs using any languages you have to learn it by
doing! You have to write as many different programs using as many
different algorithms. You have to break codes, make errors, debug errors
and sometimes you have to approach the same problem using 2 or 3
different logics. To learn “C language”
efficiently, you must write a lot of different C programs using the
concepts of C language. To do this you need a good compiler for C
language setup on your computer. Turbo C is one such compiler for
windows operating system. If you are running a Linux operating system,
you can use the GCC compiler. A compiler does the job of converting codes written in C language to machine language, so that it can be executed.
First of all you need to install and setup Turbo C compiler on your computer. If you are using Windows XP – you can download Turbo C
and install it directly. On the other hand if you are using Windows
Vista or Windows 7 – you may read the following article to setup Turbo C
on your computer.
How to install Turbo C/C++ on Windows 7/Vista
Okay. I assume that you have installed
Turbo C on your computer perfectly. Now lets see how to use Turbo C to
RUN your C programs.
Open Turbo C from your Desktop or Programs menu. Select “File” from Menu bar and select option “New”
If there are any default lines of code
present inside editor please remove all of them. The text editor should
be blank. Now you may type in the following program in your Turbo C
editor. This is a program to print “Hello World” on the first line of your output screen and to print “Thank You” on the next line of your output screen.
Note:-
You don’t need to type any lines that comes after // in your Turbo C
editor. Any text that is placed after // are comments and are written
here with C code for your ease of understanding.
#include//Preprocessing standard input output header file
##includevoid main() // Main function which is the entry point to any C program
{
printf("Hello World\n"); // Function to print any data on output screen
printf("Thank You");
getch(); // Function get an input data from keyboard
}
If you are really new to C programming
you may not understand this simple lines of code perfectly. Don’t worry
about that, we will learn those in coming chapters. First of all keep
in mind that C is a procedural programming language – which means these codes are executed line by line; beginning from the first line #include.
The first two lines that begins with #include are 2 preprocessors
(which we will explain later). The line void main() is where the real
codes of program begin. You may note 2 parentheses { } that follows void
main(). The whole program must be kept within these 2 parentheses. So
your C programs skeleton would be like
Preprocessors
void main()
{
Lines of code/Program
}
printf() is a standard
command/library function in C language which performs the task of
printing some data on the output screen. What ever data we pass through
the enclosed parentheses () of printf function will get printed on the output screen and the data can be integers,characters or strings. So the line printf(“Hello World\n”); will print Hello World on the output screen. You may note the \n that follows Hello World. That \n is the command for new line.
The printf function will move the cursor of output screen to next line
upon reading the \n sequence inside the parentheses. Now in next line printf(“Thank You”); will print the words Thank You
Note:- Almost all the lines of code inside the void main () { lines of code }
must end with a semicolon. There are exceptions in some cases like
usage of loops (for, do while) etc which we will learn later.
The last line of code getch() is actually a standard input library function in C language. getch()
-known as get character- is a function get an input from the keyboard.
Upon executing the getch() function the program control will wait until a
character is inputted by the user from keyboard. Here in
this program this getch() function is used as a trick to hold the output
screen live for a desired period of time by the user. The output screen will get closed only if the user makes a key press.
Note:- You may try executing this program without getch() function. Observe yourself what happens!
I hope that’s enough for a basic explanation of the program. If you still have doubts please ask through comments. Now lets RUN this program using Turbo C. Before going into the steps, you may SAVE your C program. Select “File” from menu -> click-> Save. Name the files as ->hello.c or some other name with a .c extension. See the screen shot below.
How to Compile a C program in Turbo C ?
The first step is compiling. Compiling makes sure your program is free of syntax errors.
How ever compiler won’t check for any logical/algorithmic errors. There
is a lot of process that happens while the compiler compiles a program –
which we will discuss later in coming articles. To do compiling – Select -> Compile from menu and click-> compile. See the image below.
After compiling, you will see a dialog box as shown below.If the compilation is success – you will see a “success” message. Else you will see the number of errors. Both are shown using screen shots.
The screen shot of a “success” compilation
The screen shot of an “Error” compilation.
Here the 2 errors are because I removed semicolons from the 2 lines
printf(“Hello World\n”)
printf(“Thank You”)
You may run the program only after a “Successful” compilation. Make your program free of errors before you RUN the program.
How to RUN a C Program in Turbo C compiler?
To RUN the program – you may select ->Run from menu and click -> Run (as shown in the image below).
Now you will see the output screen as shown in the screen shot below.
To close the output screen press any key (please remember/refer the part I mentioned about getch() function in this article).
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