Temperature conversion function in C

#include<stdio.h>

double cf(double fahrenheit)

{

   return (5.0/9.0) * (fahrenheit-32);

}

double main()

{

   double celsius;

   double fahrenheit;

   printf("Enter the temperature in degrees fahrenheit:\n");

   scanf("%lf", &fahrenheit);

   celsius = cf(fahrenheit);

   printf ("result %lf\n", celsius);

   return 0;

}