This
blog inform you about the general structure and keywords of C language.
C program basically has
the following form:
- Preprocessor Commands
- Functions
- Variables
- Statements & Expressions
- Comments
The following program is written in
the C programming language:
|
#include <stdio.h>
int main()
{ /* My first program */
printf("Hello, World!
\n");
return 0;
|
Preprocessor
Commands: These commands tells the compiler
to do preprocessing before doing actual compilation. Like #include
<stdio.h> is a preprocessor command which tells a C compiler to
include stdio.h file before going to actual compilation. You will learn more
about C Preprocessors in C Preprocessors session.
Functions: are main building blocks of any C
Program. Every C Program will have one or more functions and there is one
mandatory function which is called main() function. This function is
prefixed with keyword int which means this function returns an integer
value when it exits. This integer value is returned using return
statement.
The C Programming language provides
a set of built-in functions. In the above example printf() is a C
built-in function which is used to print anything on the screen. Check Builtin function section for more detail.
You will learn how to write
your own functions and use them in Using Function session.
Variables: are used
to hold numbers, strings and complex data for manipulation. You will learn in
detail about variables in C Variable Types.
Statements &
Expressions : Expressions
combine variables and constants to create new values. Statements are
expressions, assignments, function calls, or control flow statements which make
up C programs.
Comments: are used
to give additional useful information inside a C Program. All the comments will
be put inside /*...*/ as given in the example above. A comment can span through
multiple lines.
Note the followings
- C is a case sensitive programming language.
- It means in C printf and Printf will have different meanings.
- End of each C statement must be marked with a semicolon.
- Multiple statements can be one the same line.
- White Spaces (ie tab space and space bar ) are ignored. Statements can continue over multiple lines.
