how to use using in header file?

[lallous]

Hello

file.h
#include <string>
#include <vector>

//spot1
class StringVec
{
private:
std::vector<std::string> list;
public:
void add(const std::string val);
};

etc...

Now, since "file1.h" will be used in other source code modules, it is not
good to put "using namespace std" @ spot1.
How can I then declare that StringVec class is using 'std' namespace so that
I don't write 'std::XXX' everytime in the class?

 

[Thomas Matthews]

Hello

file.h
#include <string>
#include <vector>

//spot1
class StringVec
{
private:
std::vector<std::string> list;
public:
void add(const std::string val);
};

etc...

Now, since "file1.h" will be used in other source code modules, it is not
good to put "using namespace std" @ spot1.
How can I then declare that StringVec class is using 'std' namespace so that
I don't write 'std::XXX' everytime in the class?

file.h
#include <string>
#include <vector>
using std::string;
using std::vector

//spot1
class StringVec
{
private:
vector<string> list;
public:
void add(const string val);
};

Some notes:
1. Use a typedef for your container. This will make
life easier:
typedef vector<string> String_List;
// ...
String_List list;

2. Pass strings and other structures by reference not
by value:
void add(const string & val);
Notice the '&' after 'string'.


--
Thomas Matthews

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Other sites:
http://www.josuttis.com -- C++ STL Library book
http://www.sgi.com/tech/stl -- Standard Template Library

 

[Nick Hounsome]

file.h
#include <string>
#include <vector>
using std::string;
using std::vector

This is bad because you have bought std::string and std::vector into the
global namespace
for every file that includes this header.

//spot1
class StringVec
{
private:
vector<string> list;
public:
void add(const string val);
};

Some notes:
1. Use a typedef for your container. This will make
life easier:
typedef vector<string> String_List;

Better:

typedef std::string string;

// ...
String_List list;

Why would he want a class called StringVec to be implemented with a variable
called list which is actually a vector?

2. Pass strings and other structures by reference not
by value:
void add(const string & val);
Notice the '&' after 'string'.

Why not stick to STL terminology and call it push_back?
Why not just use std::vector?