head file inclusions

[Gary Wessle]

Hi

in a header file I have

********************************
#ifndef READ_DATA_H
#define READ_DATA_H


#include <string>
using string::string; <<---- line 6
********************************

but when I $make I get error in reference to using string::string
fred@debian:~/myPrograms/common$ make
g++ -c -o read_data.o read_data.cpp
read_data.h:6: error: 'string' has not been declared
read_data.h:6: error: expected nested-name-specifier before 'string'
read_data.h:6: error: 'string' has not been declared

 

[Victor Bazarov]

Hi

in a header file I have

********************************
#ifndef READ_DATA_H
#define READ_DATA_H


#include <string>
using string::string; <<---- line 6

Did you mean

using std::string;

??

BTW, 'using' declarations and directives in the global scope are
really *not* recommended in a header. Why do you think you need
it?

********************************

but when I $make I get error in reference to using string::string
fred@debian:~/myPrograms/common$ make
g++ -c -o read_data.o read_data.cpp
read_data.h:6: error: 'string' has not been declared
read_data.h:6: error: expected nested-name-specifier before 'string'
read_data.h:6: error: 'string' has not been declared

V

 

[Gary Wessle]

Did you mean

using std::string;

??

BTW, 'using' declarations and directives in the global scope are
really *not* recommended in a header. Why do you think you need
it?

because I need to use "string" in the argument of one of the public
member functions as below

#ifndef READ_DATA_H
#define READ_DATA_H


#include <string>
using std::string;


class read_data
{
int number_of_lines;
string file_name;

public:
read_data(string); //<<-------- this
~read_data();
int get_number_of_lines();

};


#endif

 

[Ian Collins]

because I need to use "string" in the argument of one of the public
member functions as below

No, you don't. You just type std::string. Never put using directives
in headers!

 

[Kai-Uwe Bux]

because I need to use "string" in the argument of one of the public
member functions as below

You don't need the using directive.

#ifndef READ_DATA_H
#define READ_DATA_H


#include <string>
using std::string;

Ditch the using thing.

class read_data
{
int number_of_lines;
string file_name;

public:
read_data(string); //<<-------- this

Do:

read_data( std::string );

 

[Victor Bazarov]

You don't need the using directive.


Ditch the using thing.


Do:

read_data( std::string );

Or better:

read_data(std::string const&);

V