question: std:string and float values??

[Woodster]

I am starting to use templates and have managed to figure out how to use
std::string, std::map and make_pair successfully so far (Yeah I know -
not much of a big step but I'm getting there)

Previously I was using something like:

char *buffer[50];
double value = 10.5;

sprintf(buffer, "text %.2f text", value);

How should I do this using an std:string in the place of the buffer
variable?

Thanks in advance

Sean Hannan

[Senthilvel Samatharman]

Re: question: std:string and float values??

Woodster wrote:
[color=blue]
> I am starting to use templates and have managed to figure out how to use
> std::string, std::map and make_pair successfully so far (Yeah I know -
> not much of a big step but I'm getting there)
>
> Previously I was using something like:
>
> char *buffer[50];
> double value = 10.5;
>
> sprintf(buffer, "text %.2f text", value);
>
> How should I do this using an std:string in the place of the buffer
> variable?[/color]

Use stringstream

#include <iostream>
#include <sstream>

int main()
{
std:: stringstream str;
double value = 10.5;

str<<"text "<<value<<" text";

string buffer(str.str( ));

std::cout<<buff er;

return 0;
}

This is how i'd do .. mabe experts here can show you a better way..

[color=blue]
>
>
> Thanks in advance
>
> Sean Hannan[/color]

[Senthilvel Samatharman]

Re: question: std:string and float values??

>

Sorry a small correction in the program
[color=blue]
>
> Use stringstream
>
> #include <iostream>
> #include <sstream>[/color]

#include <string> // I missed it last time...
[color=blue]
>
>
> int main()
> {
> std:: stringstream str;
> double value = 10.5;
>
> str<<"text "<<value<<" text";
>
> std::string buffer(str.str( )); //In my last post it was just string...not
> std::string.
>
> std::cout<<buff er;
>
> return 0;
> }
>
> This is how i'd do .. mabe experts here can show you a better way..
>[color=green]
> >
> >
> > Thanks in advance
> >
> > Sean Hannan[/color][/color]

[Woodster]

Re: question: std:string and float values??

In article <3FB32FD0.3ED03 605@adcc.alcate l.be>,
Samatharman.Sen thilvel@adcc.al catel.be says...[color=blue]
> Use stringstream
>
> #include <iostream>
> #include <sstream>
>
> int main()
> {
> std:: stringstream str;
> double value = 10.5;
>
> str<<"text "<<value<<" text";
>
> string buffer(str.str( ));[/color]

Only problem is that this does not allow formatting of the variable (ie:
%.2f in this case). Is there a way I can still format the variable
'value'

Sean Hannan

[Frank Schmitt]

Re: question: std:string and float values??

Woodster <mirror@127.0.0 .1> writes:
[color=blue]
> In article <3FB32FD0.3ED03 605@adcc.alcate l.be>,
> Samatharman.Sen thilvel@adcc.al catel.be says...[color=green]
> > Use stringstream
> >
> > #include <iostream>
> > #include <sstream>
> >
> > int main()
> > {
> > std:: stringstream str;
> > double value = 10.5;
> >
> > str<<"text "<<value<<" text";
> >
> > string buffer(str.str( ));[/color]
>
> Only problem is that this does not allow formatting of the variable (ie:
> %.2f in this case). Is there a way I can still format the variable
> 'value'[/color]

use std::setprecisi on:

#include <iomanip>
#include <sstream>

int main() {
std:: stringstream str;
double value = 10.5;

str << std::setprecisi on(2) << "text " << value << " text";
string buffer(str.str( ));
....

HTH & kind regards
frank

--
Frank Schmitt
4SC AG phone: +49 89 700763-0
e-mail: frankNO DOT SPAMschmitt AT 4sc DOT com

[Senthilvel Samatharman]

Re: question: std:string and float values??

Woodster wrote:
[color=blue]
> In article <3FB32FD0.3ED03 605@adcc.alcate l.be>,
> Samatharman.Sen thilvel@adcc.al catel.be says...[color=green]
> > Use stringstream
> >
> > #include <iostream>
> > #include <sstream>
> >
> > int main()
> > {
> > std:: stringstream str;
> > double value = 10.5;
> >
> > str<<"text "<<value<<" text";
> >
> > string buffer(str.str( ));[/color]
>
> Only problem is that this does not allow formatting of the variable (ie:
> %.2f in this case). Is there a way I can still format the variable
> 'value'[/color]

Use setprecision of <iomanip>
Think this is what you ask for

#include <iostream>
#include <sstream>
#include <string>
#include <iomanip>

int main()
{
std:: stringstream str;
double value = 10.590878;

str<<"text "<<std::setprec ision(5)<<value <<" text"; //--> value will have
exactly five digits( before decimal point + after decimal point)

std::string buffer(str.str( ));

std::cout<<buff er;

return 0;
}
[color=blue]
>
>
> Sean Hannan[/color]

[Jon Bell]

Re: question: std:string and float values??

In article <MPG.1a1dbefcde df150498968a@ne ws.westnet.com. au>,
Woodster <mirror@127.0.0 .1> wrote:[color=blue]
>In article <3FB32FD0.3ED03 605@adcc.alcate l.be>,
>Samatharman.Se nthilvel@adcc.a lcatel.be says...[color=green]
>> Use stringstream
>>
>> #include <iostream>
>> #include <sstream>
>>
>> int main()
>> {
>> std:: stringstream str;
>> double value = 10.5;
>>
>> str<<"text "<<value<<" text";
>>
>> string buffer(str.str( ));[/color]
>
>Only problem is that this does not allow formatting of the variable (ie:
>%.2f in this case). Is there a way I can still format the variable
>'value'[/color]

Sure, use stream manipulators just like you would if you were writing to
cout or a file. I'm not completely "up" on C-style formatting so I'm not
sure exactly what format you want, but this might come close:

str << "text " << fixed << setprecision(2) << value << " text";

--
Jon Bell <jtbellap8@pres by.edu> Presbyterian College
Dept. of Physics and Computer Science Clinton, South Carolina USA

[Woodster]

Re: question: std:string and float values??

Thanks for the prompt response from all who replied. This will get me
going for what I am trying to do.

Regards

Sean Hannan

In article <bp02ep$aj8$2@j tbell.presby.ed u>, jtbellq2f@presb y.edu
says...[color=blue]
> In article <MPG.1a1dbefcde df150498968a@ne ws.westnet.com. au>,
> Woodster <mirror@127.0.0 .1> wrote:[color=green]
> >In article <3FB32FD0.3ED03 605@adcc.alcate l.be>,
> >Samatharman.Se nthilvel@adcc.a lcatel.be says...[color=darkred]
> >> Use stringstream
> >>
> >> #include <iostream>
> >> #include <sstream>
> >>
> >> int main()
> >> {
> >> std:: stringstream str;
> >> double value = 10.5;
> >>
> >> str<<"text "<<value<<" text";
> >>
> >> string buffer(str.str( ));[/color]
> >
> >Only problem is that this does not allow formatting of the variable (ie:
> >%.2f in this case). Is there a way I can still format the variable
> >'value'[/color]
>
> Sure, use stream manipulators just like you would if you were writing to
> cout or a file. I'm not completely "up" on C-style formatting so I'm not
> sure exactly what format you want, but this might come close:
>
> str << "text " << fixed << setprecision(2) << value << " text";
>
>[/color]

[Jon Bell]

Re: question: std:string and float values??

In article <MPG.1a1da53f84 43d74989689@new s.westnet.com.a u>,
Woodster <mirror@127.0.0 .1> wrote:[color=blue]
>
>char *buffer[50];
>double value = 10.5;
>
>sprintf(buffer , "text %.2f text", value);
>
>How should I do this using an std:string in the place of the buffer
>variable?[/color]

#include <cstdio>
#include <iostream>
#include <iomanip>
#include <string>
#include <sstream>

using namespace std;

int main ()
{
// C-style method

double value = 10.5;
char buf[80];
sprintf (buf, "text %.2f text\n", value);
cout << buf;

// C++-style method

ostringstream bufstream;
bufstream << "text "
<< fixed << setprecision(2) << value
<< " text\n";
cout << bufstream.str() ;

return 0;
}


--
Jon Bell <jtbellap8@pres by.edu> Presbyterian College
Dept. of Physics and Computer Science Clinton, South Carolina USA