declare variable double xxx= 0.0f; vs. double xxx= 0.0;

Question

Hi,

A dumb question, I noticed this notation in the code I was analyzing.  What does it mean?

double xxx= 0.0f;
 vs.
double xxx= 0.0;

I guess the "f" just stands for float but why is this necessary?

Thanks

Answer 1

0.0f forces the number to be treated as a single precision floating point number (float).  Normally, you'd only use this for assigning to a float:

float xxx = 0.0f;

When you do:

double xxx = 0.0;

It uses the standard, which is equivalent to:

double xxx = 0.0l;  // long double


For full details, see Literals (C++) , and more specifically, C++ Floating-Point Constants .


However, since a float can be assigned to a double and widens automatically, in your case, you get the same value.

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Reed Copsey, Jr. - http://reedcopsey.com