Re: copying contents from a char array to std::string obj

From:
"Alf P. Steinbach" <alfps@start.no>
Newsgroups:
comp.lang.c++
Date:
Thu, 24 Jul 2008 07:31:08 +0200
Message-ID:
<m6OdndEepo25jhXVnZ2dnUVZ_s7inZ2d@posted.comnet>
* Ramesh:

Hi.

Assuming I have a code snippet like below:

#include <iostream>
using namespace std;

char Mac[6] = { 0x0, 0x1, 0x2, 0x3, 0x4, 0x5 };
std::string csMac;

1. Whats the best way to do a deep copy from the c-style char array to
the c++ string object.


"best" is not meaningful without some criteria.

And as Christian Hackl remarked else-thread you're probably better off using
some other container type, not a string.

One way to initialize a std::string from the data is

     #include <iostream>
     #include <string>

     template< typename T, size_t N >
     T const* begin( T const (&a)[N] ) { return a; }

     template< typename T, size_t N >
     T const* end( T const (&a)[N] ) { return a + N; }

     int main()
     {
         using namespace std;

         static char const macValues[6] = { 0x0, 0x1, 0x2, 0x3, 0x4, 0x5 };
         std::string const mac( begin(macValues), end(macValues) );

         for( size_t i = 0; i < mac.length(); ++i )
         {
             cout << (int) mac[i] << ' ';
         }
         cout << endl;
     }

I know the other way around to assign to the string object (to use a
c_str() on the string).


That's not "the other way", that's a conversion to pointer to zero-terminated
string. You don't have a zero-terminated string in the first place.

Cheers, & hth.,

- Alf

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