How to assign the value of a variable to a Fl_Output widget

[jorgem...@gmail.com]

I have a global integer variable in my code (called intFlipCount) that I need to assign to a Fl_Output widget. The following is the Fl_Output control:

Fl_Output* outFlipCount = new Fl_Output(400, 550, 50, 25, "Flip count");

I searched for information about how to get what I need and found the following link: https://www.gidforums.com/t-5915.html. However, I do not know how to apply it for my case.

I will very much appreciate any help you can provide.

Respectfully,

Jorge Maldonado

[Greg Ercolano]

On 04/23/15 15:09, jorgem...@gmail.com wrote:
> I have a global integer variable in my code (called intFlipCount) that
> I need to assign to a Fl_Output widget. The following is the Fl_Output control:
>
> Fl_Output* outFlipCount = new Fl_Output(400, 550, 50, 25, "Flip count");

You can use sprintf() to get it into a string, then use Fl_Output's
value() method to apply that string to it. e.g.

char s[40];
sprintf(s, "%d", intFlipCount);
outFlipCount->value(s);

[jorgem...@gmail.com]

I am very grateful for all the help you have provided to this and other 2 questions because you have solved critical issues for a final project that is extremely important to me. I hope you do not mind if I keep asking additional questions, although before posting a new one I always try to solve it by myself. Sometimes I find an answer but sometimes I do not.

Best regards,

Jorge Maldonado

[Greg Ercolano]

On 04/23/15 17:40, jorgem...@gmail.com wrote:
> I am very grateful for all the help you have provided to this and other 2 questions because you have solved critical issues for a final project that is extremely important to me. I hope you do not mind if I keep asking additional questions, although before posting a new one I always try to solve it by myself. Sometimes I find an answer but sometimes I do not.

Fire away.. if I can't reply, other folks here will..

[Edzard Egberts]

Greg Ercolano wrote:
> On 04/23/15 15:09, jorgem...@gmail.com wrote:

>> I have a global integer variable in my code (called intFlipCount) that
>> I need to assign to a Fl_Output widget. The following is the Fl_Output control:
>>
>> Fl_Output* outFlipCount = new Fl_Output(400, 550, 50, 25, "Flip count");
>

> You can use sprintf() to get it into a string, then use Fl_Output's
> value() method to apply that string to it. e.g.
>
> char s[40];
> sprintf(s, "%d", intFlipCount);
> outFlipCount->value(s);
>

std::ostringstream OS;
OS << intFlipCount;
outFlipCount->value(OS.str().c_str());

The main difference - this kind of code never will cause a buffer
overflow. This time s[40] for sure is big enough for an integer, but as
far as I know, estimating buffer lengths continues to cause vulnerable
programs.

[Greg Ercolano]

On 04/23/15 23:22, Edzard Egberts wrote:

> Greg Ercolano wrote:
>> You can use sprintf() to get it into a string, then use Fl_Output's
>> value() method to apply that string to it. e.g.
>>
>> char s[40];
>> sprintf(s, "%d", intFlipCount);
>> outFlipCount->value(s);
>>
> std::ostringstream OS;
> OS << intFlipCount;
> outFlipCount->value(OS.str().c_str());
>
> The main difference - this kind of code never will cause a buffer
> overflow. This time s[40] for sure is big enough for an integer, but as
> far as I know, estimating buffer lengths continues to cause vulnerable
> programs.

Tis true..

"snprintf()" (emphasis on 'n') can get you around some of that.
But the STL approach is certainly better; no worries for space.

[Martin McDonough]

Or just use std::to_string if you don't want to involve stream objects :)