Program:
- C program consists variables and functions.
- Program execution starts with main() function automatically.
Main.c
| #include<stdio.h> void main() { printf(“Hello”); } |
Application:
- C application contains more than one program.
- We connect these programs by calling one program functions from another program.
- We connect these programs using #include.
- Only one program contain main() function from which application execution starts.
| Main.c | Arithmetic.c |
| #include<arithmetic.c> void main() { // invoking functions add(); subtract(); } | #include<stdio.h> void add() { printf(“Add”); } void subtract() { printf(“Subtract”); } |
#include:
- A pre-processor directive is used to connect the programs in C application.
Library:
- Library is a collection of pre-define programs called Header-files.
- Header-file contains Variables and Methods.
- Library is used to develop C application quickly.
- Some of the header file names as follows:
| stdio.h | math.h | conio.h | string.h | graphics.h |
| printf() scanf() | sqrt() rand() | clrscr() getch() | strlen() strrev() | circle() line() |