Write a program to calculate area and circumference of circle using inline function

#include<iostream.h>
#include<conio.h>
const pi=3.1459;
inline float circum(float x)
{
  return(2*pi*x);
}
inline float area(float x)
{
   return (pi*x*x);
}
void main()
{
  float r;
  clrscr();
  cout<<"\nEnter the radius of a circle:";
  cin>>r;
  cout<<"\nCircumference:"<<circum(r);
  cout<<"\nArea :"<<area(r);
  getch();
}