Cannot understand a C++ line

Question

I am reading a C++ code and came across a function:

double Nm_poissons_ratio(double /*Temp*/)

{

  double PR(0.0);

  PR = 0.31;

  return PR;

}

I don't understand what is the effect of /* */ characters which surround the Temp variable.

Thanks

Answer 1

All that is happening is the developer is commenting out a piece of code. Basically a comment tells the computer to ignore this piece of code. So, if you were developing a programming you would:

/* This is hidden to everyone BUT the programmer. */

Answer 2

It means that the function takes a double argument, but they are commenting out the name (hence the /* */) because the argument to be named.

Likely because the compiler will warn them about an unused formal argument, since they do not use Temp anywhere in the function.

Answer 3

If you write

double Nm_poissons_ratio(double Temp)

the compiler will warning. about an unused variable.

In this case, the coder wanted to retain the signature for some reason, but to avoid the warning. He/she therefore put a comment to show what it originally was.

---

Why is this the signature? It's hard to know.

• Perhaps this is an intermediate version of the code, and he/she plans to use this parameter in the future (this is actually an excellent case to retain the warning).

• Perhaps it's passed as a callback to some function that expects a specific signature.