Introduction to C

A sample of C language program

Example of C program to calculate area of circle:

Explanation of above program :

# is the preprocessor directive which commands that the content of file should be included at the time of compilation.

< stdio.h> is the header file which contains all input and output functions like scanf(), printf() which are frequently used in c programs.

main() is the first function which is executed by a C program.

1. int a,r=5; -> This statement declares 2 variables a and r of type integer and r has been assigned a value of 5.

2. const pi=3.14; -> This statement declares pi as constant and value 3.14 has been assigned to it.

3. a = pi * r *r; -> This statement computes the area of circle and assign it to variable a

4. printf("%f",a); -> This statement prints the area of circle using printf function.

5. getch(); -> It is used to get character from user.

Note: /* Any thing written within it is consider as comment statements. */

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