error: called object is not a function

That's the error message I get when I try to compile this program. Is there something wrong with my functions or how I'm calling them?

Code:

#include <stdio.h>

float celsius(float);
float fahrenheit(float);

int main()
{
   float celsius, fahrenheit;
 
   printf("%10s%10s", "celsius", "fahrenheit");

   for (celsius = 0; celsius <= 100; ++celsius)
      printf("%10.2f%10.2f\n", celsius, fahrenheit( celsius ) );

   printf("\n\n\n");

   for (fahrenheit = 32; fahrenheit <= 212; ++fahrenheit)
      printf("%10.2f%10.2f\n", fahrenheit, celsius(fahrenheit) );

   printf("\n");

   return 0;
}


float celsius (float fahrenheit)
{
float celsius;
celsius = (fahrenheit - 32) / 1.8;
return celsius;
}

float fahrenheit (float celsius)
{
return (celsius * 9 / 5) + 32;
}

you used variables with the same name than functions.

don't do that. Always use different names, for the function you could use something like "farTocel", and the vars are far and cel.