All the C Program are divided into many parts
such as :
•
Preprocessor Commands
•
Functions
•
Variables
•
Statements and Expressions
•
Comments
Preprocessor
Commands :-
Preprocessor
Command is not a part of the compiler of c language but it is a diffrent step
in the compilation time. All
preprocessor commands starts with a (#) symbol.
Example :-
#define Substitutes a preprocessor
macro
#include Inserts a particular header from
another file
#undef Undefines
a preprocessor macro
#ifdef Returns true if this macro
is defined
#ifndef Returns true if this macro is
not defined
#if Tests if a compile
time condition is true
#else The alternative for #if
#elif #else an #if in one
statement
#endif Ends preprocessor conditional
#error Prints error message on
stderr
#pragma Issues special commands to the
compiler, using a standardized method
Main() Function :-
we all know why main function is
used in c programs because when we run the program at that time program
execution start with the main Function.
Syntax :-
int main()
{
// code write here
return 0;
}
Comments :-
Comments are the
statements that are ignored by the
compiler.
Syntax :-
Multiline Comments :-
/*
Comments statement that put here
*/
Singleline Comments
:-
// Comment statement put here for single line
comments
Example of Hello
World Program :-
#include<stdio.h> //Preprocessor
Commands
int main()
//main() program execution start
to here
{
/* hello word program in c */ //comments statements
printf(“Hello World…..\n”);
return 0;
}