PROGRAM-1
AIM: To learn about the C Library, Preprocessor directive, Input- output statement.
SOFTWARE REQUIRED: Turbo C/C++
THEORY:
●C Libraries:
A library in C consists of pre- defined functions, constant keywords and header
files like <stdio.h>, <conio.h>, <string.h>, <stdlib.h>, etc. A library in C is a
group of functions and declarations, exposed for use by other programs.
a) <stdio.h>: Defines core input and output functions like printf( ),
scanf( ).
b) <conio.h>: Contains functions for Console input/output functions like
clrscr( ), getch( )
c) <string.h>: Defines string handling functions like strrev( ), strlen( ),
strcpy(), strcmp( ), strcat( ).
●Preprocessor Directives:
Preprocessor programs provide preprocessors directives which tell the compiler
to preprocess the source code before compiling. All of these preprocessor
directives begin with a „#‟ (hash) symbol. This („#‟) symbol at the beginning of a
statement in a C/C++ program indicates that it is a pre-processor directive. We
can place these preprocessor directives anywhere in our program. Examples of
some preprocessor directives are: #include, #define, #ifndef etc.
●Input- Output Statements:
Input means to provide the program with some data to be used in the program
and Output means to display data on screen or write the data to a printer or a file.
C programming language provides many built-in functions to read any given
input and to display data on screen when there is a need to output the result.
There are two types of input- output functions:
1. Formatted Input- Output Functions: printf( ), scanf( ).
2. Non- Formatted Input- Output Functions: getche( ), getch( ), putch( ),
putche( ), etc.
