streams and floaters

[Noah Roberts]

I have a double that contains the value 1000000. I want to print
"1000000". Just doing this:

str << doub;

results in "1e+006". Attempting this:

str << std::fixed << doub;

results in "1000000.000000"

str << std::fixed << std::noshowpoint << doub

results in the same.

From what I am reading, the last should be exactly what I want but it

isn't resulting in what I want. What is the correct way?

 

[BRG]

I have a double that contains the value 1000000. I want to print
"1000000". Just doing this:

str << doub;

results in "1e+006". Attempting this:

str << std::fixed << doub;

results in "1000000.000000"

str << std::fixed << std::noshowpoint << doub

results in the same.

isn't resulting in what I want. What is the correct way?

str << std::fixed << std::noshowpoint << std::setprecision(0) << doub

should work.

Brian Gladman

 

[Noah Roberts]

str << std::fixed << std::noshowpoint << std::setprecision(0) << doub

Doesn't setprecision(0) also shut off after the decimal if I have a
value that needs it?

 

[BRG]

Doesn't setprecision(0) also shut off after the decimal if I have a
value that needs it?

Yes.

If this matters to you you will need to test if your number is an
integer and set the argument to setprecision accordingly. Something like:

str << std::fixed << std::noshowpoint
<< std::setprecision(x == std::floor(x) ? 0 : 5) << x;

Brian Gladman