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can any one translate the following codes into c++ codes, coz i can't run
the "printf" command in Unix and it said it's implicit declaration.
Is it only the two lines with comment need to be re-written??
Thanks a lot

void _display_number(int v, int n){
if(v >= 1000){
int r = v % 1000;
_display_number(v / 1000,n);
printf(",%03d",r); // how to translate that into
std::cout<<...?
}else{
printf("%s%d\n",n ? "-":"",v); // how to translate
}
}

void display_number(int v){
_display_number(v < 0 ? -v : v,v < 0);
}

"news.hku.hk" <> wrote in message
news:...
> can any one translate the following codes into c++ codes, coz i can't run
> the "printf" command in Unix and it said it's implicit declaration.

Probably because you failed to #include the required
header, <cstdio> or <stdio.h>. 'printf()' works just
fine with C++.

> Is it only the two lines with comment need to be re-written??
> Thanks a lot
>
> void _display_number(int v, int n){
> if(v >= 1000){
> int r = v % 1000;
> _display_number(v / 1000,n);
> printf(",%03d",r); // how to translate that
into
> std::cout<<...?

std::cout << ',' << std::setw(3) << r;


> }else{
> printf("%s%d\n",n ? "-":"",v); // how to translate

std::cout << n ? "-" : "" << v << '\n';

> }
> }
>
> void display_number(int v){
> _display_number(v < 0 ? -v : v,v < 0);
> }

-Mike

Mike Wahler <> spoke thus:

>> printf(",%03d",r); // how to translate that

> std::cout << ',' << std::setw(3) << r;

Note that the default fill character is a space - I think you forgot

std::setfill('0');

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cyberspace.org | don't, I need to know. Flames welcome.

news.hku.hk <> spoke thus:

> can any one translate the following codes into c++ codes, coz i can't run
> the "printf" command in Unix and it said it's implicit declaration.
> Is it only the two lines with comment need to be re-written??

Please don't multipost in the future. Thanks.

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cyberspace.org | don't, I need to know. Flames welcome.

"Christopher Benson-Manica" <> wrote in message
news:c6u6al$3r8$...
> Mike Wahler <> spoke thus:
>
> >> printf(",%03d",r); // how to translate that
>
> > std::cout << ',' << std::setw(3) << r;
>
> Note that the default fill character is a space - I think you forgot
>
> std::setfill('0');

Yes,thanks.

-Mike

Thanks much for all your suggestion. And i won't multipost anymore. Just
another question. As printf is for output to screen, what if i want to
output the result into a text file.

i've written:
__________________________________
ofstream of ("abc.txt", ios:ut);
if (!ofs){
cerr << "Error" << endl;
return 1;
}
display_number(1234567; // this just output to screen. But how to change
the function "display_number" to output the result to abc.txt???or is there
any simpler ways ????
________________________________
Thanks all !

"news.hku.hk" <> wrote in message
news:...
> can any one translate the following codes into c++ codes, coz i can't run
> the "printf" command in Unix and it said it's implicit declaration.
> Is it only the two lines with comment need to be re-written??
> Thanks a lot
>
> void _display_number(int v, int n){
> if(v >= 1000){
> int r = v % 1000;
> _display_number(v / 1000,n);
> printf(",%03d",r); // how to translate that
into
> std::cout<<...?
> }else{
> printf("%s%d\n",n ? "-":"",v); // how to translate
> }
> }
>
> void display_number(int v){
> _display_number(v < 0 ? -v : v,v < 0);
> }
>
>

"news.hku.hk" <> wrote in message
news:40931a87$...
> Thanks much for all your suggestion. And i won't multipost anymore. Just
> another question. As printf is for output to screen, what if i want to
> output the result into a text file.
>
> i've written:
> __________________________________
> ofstream of ("abc.txt", ios:ut);
> if (!ofs){
> cerr << "Error" << endl;
> return 1;
> }
> display_number(1234567; // this just output to screen. But how to change
> the function "display_number" to output the result to abc.txt???or is
there
> any simpler ways ????

This is a simple way, this is the only way in C++. You need to pass the
destination you want to display to as a parameter to display_number and
_display_number, that means you are going to have to rewrite _display_number
to use C++ I/O instead of printf.

void _display_number(ostream& os, int v, int n){
...
}


void display_number(ostream& os, int v){
_display_number(os, v < 0 ? -v : v,v < 0);
}

ofstream ofs("abc.txt", ios:ut);
if (!ofs){
cerr << "Error" << endl;
return 1;
}
display_number(ofs, 1234567;

Now I think you should have a go at rewriting _display_number yourself.
Instead of cout << ..., you use the parameter passed in like this, os << ...

john