No Previous prototype for function

[Darkel]

I entered and ran program 13.4.  Curiously I got the warning message "No previous prototype for function".  The program ran fine but the warning was there.

After a little searching on the internet  someone suggested I simply define a function prototype at the top of my file as such:

void calculateTriangularNumber (int n);

// Function to calculate the nth triangular number

void calculateTriangularNumber (int n)
{
 blah blah blah
}

and so on.

This made the error go away.

Why?

[bright]

I think it is similar to a method declaration in the interface section which declares the method and ends with a semicolon whereas the implementation of the method does not end with a semicolon and has open and closed curly braces.