/****************************************************************************/
/* area_cal : Area calculation program				            */
/* This program gives area of a circle based on the radius                  */
/* given by the user							    */
/*									    */
/* Written by: Vinita Bhatia						    */
/* Revision 0: June 1, 1996 						    */
/*									    */
/****************************************************************************/

#include <stdio.h>
#include <math.h&rt

#define PI	M_PI

main()
{
    float r;			/* radius         		*/

    printf( "Area calculation Program.\n" );
    printf( "Enter the radius? " );
    scanf( "%f", &r );
    printf( "Area is : %f\n", PI*r*r );

    return 0;
}