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From: Paul Richards on 24 Mar 2010 21:49
I am working my way through 'Accelerated C++" and have come upon a
compiler error. The code is cut'n'pasted from downloaded source from
the Accelerated C++ website. The compiler gives this error "error:'max'
not declared in this scope" (see <<< ERROR below). The program is
contained in Section 4.5, pp70-71.

As I have #included <algorithm> why would this error occur?

Thanks

====

#include <algorithm>
#include <iomanip>
#include <iostream>
#include <stdexcept>
#include <string>
#include <vector>
#include "grade.h"
#include "Student_info.h"

using std::cin; using std::setprecision;
using std::cout; using std::sort;
using std::domain_error; using std::streamsize;
using std::endl; using std::string;
using std::vector;

int main()
{
vector<Student_info> students;
Student_info record;
string::size_type maxlen = 0; // the length of the longest name

// read and store all the students' data.

while (read(cin, record)) {

maxlen = max(maxlen, record.name.size()); <<< ERROR
students.push_back(record);
}

// alphabetize the student records
sort(students.begin(), students.end(), compare);

// write the names and grades

for (vector<Student_info>::size_type i = 0;
i != students.size(); ++i) {

// write the name, padded on the right to `maxlen' `+' `1' characters
cout << students[i].name
<< string(maxlen + 1 - students[i].name.size(), ' ');

// compute and write the grade
try {
double final_grade = grade(students[i]);
streamsize prec = cout.precision();
cout << setprecision(3) << final_grade
<< setprecision(prec);
} catch (domain_error e) {
cout << e.what();
}
cout << endl;
}
return 0;
}




--
Paul
Melbourne, Australia
From: Paul Bibbings on 24 Mar 2010 22:53
"Paul Richards" <paulrichards(a)XXXNOSPAMiinet.net.au> writes:

> I am working my way through 'Accelerated C++" and have come upon a
> compiler error. The code is cut'n'pasted from downloaded source from
> the Accelerated C++ website. The compiler gives this error "error:'max'
> not declared in this scope" (see <<< ERROR below). The program is
> contained in Section 4.5, pp70-71.
>
> As I have #included <algorithm> why would this error occur?
>
> Thanks
>
> ====
>
> #include <algorithm>
> #include <iomanip>
> #include <iostream>
> #include <stdexcept>
> #include <string>
> #include <vector>
> #include "grade.h"
> #include "Student_info.h"
>
> using std::cin; using std::setprecision;
> using std::cout; using std::sort;
> using std::domain_error; using std::streamsize;
> using std::endl; using std::string;
> using std::vector;

<snip />

Having #included <iostream>, you allow simply `cin' and `cout' by adding
`using std::cin' and `using std::cout'. Similarly, having #included
<vector>, you have added `using std::vector' so that you can just use
`vector<whatever> as a type.

Merely continue that theme. Having #included <algorithm>, to use just
`max(...,...)', ...

Regards

Paul Bibbings
From: Paul Richards on 25 Mar 2010 20:30
Paul Bibbings wrote:

> "Paul Richards" <paulrichards(a)XXXNOSPAMiinet.net.au> writes:
>
> > I am working my way through 'Accelerated C++" and have come upon a
> > compiler error. The code is cut'n'pasted from downloaded source from
> > the Accelerated C++ website. The compiler gives this error
> > "error:'max' not declared in this scope" (see <<< ERROR below). The
> > program is contained in Section 4.5, pp70-71.
> >
> > As I have #included <algorithm> why would this error occur?
> >
> > Thanks
> >
> > ====
> >
> > #include <algorithm>
> > #include <iomanip>
> > #include <iostream>
> > #include <stdexcept>
> > #include <string>
> > #include <vector>
> > #include "grade.h"
> > #include "Student_info.h"
> >
> > using std::cin; using std::setprecision;
> > using std::cout; using std::sort;
> > using std::domain_error; using std::streamsize;
> > using std::endl; using std::string;
> > using std::vector;
>
> <snip />
>
> Having #included <iostream>, you allow simply `cin' and `cout' by
> adding `using std::cin' and `using std::cout'. Similarly, having
> #included <vector>, you have added `using std::vector' so that you
> can just use `vector<whatever> as a type.
>
> Merely continue that theme. Having #included <algorithm>, to use just
> `max(...,...)', ...
>
> Regards
>
> Paul Bibbings

Paul: OK, thanks. Adding using std::max did the trick.

The follow upquestion is which headers does namespace std apply to? All
of them?

--
Paul
Melbourne, Australia
From: Anand Hariharan on 26 Mar 2010 17:43
On Mar 25, 7:30 pm, "Paul Richards"
<paulricha...(a)XXXNOSPAMiinet.net.au> wrote:
> Paul Bibbings wrote:
> > "Paul Richards" <paulricha...(a)XXXNOSPAMiinet.net.au> writes:
>
> > > I am working my way through 'Accelerated C++" and have come upon a
> > > compiler error. The code is cut'n'pasted from downloaded source from
> > > the Accelerated C++ website. The compiler gives this error
> > > "error:'max' not declared in this scope" (see <<< ERROR below). The
> > > program is contained in Section 4.5, pp70-71.
>
> > > As I have #included <algorithm> why would this error occur?
>
> > > Thanks
>
> > > ====
>
> > > #include <algorithm>
> > > #include <iomanip>
> > > #include <iostream>
> > > #include <stdexcept>
> > > #include <string>
> > > #include <vector>
> > > #include "grade.h"
> > > #include "Student_info.h"
>
> > > using std::cin;                     using std::setprecision;
> > > using std::cout;                    using std::sort;
> > > using std::domain_error;            using std::streamsize;
> > > using std::endl;                    using std::string;
> > > using std::vector;
>
> > <snip />
>
> > Having #included <iostream>, you allow simply `cin' and `cout' by
> > adding `using std::cin' and `using std::cout'.  Similarly, having
> > #included <vector>, you have added `using std::vector' so that you
> > can just use `vector<whatever> as a type.
>
> > Merely continue that theme. Having #included <algorithm>, to use just
> > `max(...,...)', ...
>
> > Regards
>
> > Paul Bibbings
>
> Paul: OK, thanks. Adding using std::max did the trick.
>
> The follow upquestion is which headers does namespace std apply to? All
> of them?
>

In theory, yes. In practice however, most C headers (that are also
available to C++) tend to put their function declarations in the
global namespace.

- Anand
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