Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

Conversion from LPTSTR* to STL string

Posted on 2004-04-14
24
1,184 Views
Last Modified: 2007-12-19
Hi,
I would like to know how to convert the string from LPTSTR* to STL string object.

Sample code would be of great help.
Thanks in advance.

nt WINAPI WinMain(HINSTANCE hInstance,
                           HINSTANCE hPrevInstance,
                           LPSTR lpCmdLine,
                           int nCmdShow)
{
      LPTSTR *szArglist;
      int nArgs;
      szArglist = CommandLineToArgvW(GetCommandLineW(), &nArgs);
//I would like to convert the szArglist to STL string object

}

Regards,
Pampa
0
Comment
Question by:pampa_analytica
  • 6
  • 5
  • 5
  • +3
24 Comments
 
LVL 10

Expert Comment

by:Sys_Prog
ID: 10822031
Well  LPTSTR is infact a LPSTR if u are not using unicode characters
And LPSTR is actually a pointer to a char string
Hence this should work (I haven't tried it)

string stlStr ( szArglist ) ;

Amit
0
 
LVL 44

Expert Comment

by:Karl Heinz Kremer
ID: 10822090
That's the way to do it. It does work. "string" does have a constructor that takes a char *.
0
 

Author Comment

by:pampa_analytica
ID: 10822315
I tried in the way what Amit has posted, but it is not working. It throws me error:
f:\Viz\Viz_src\DataVizGUI\DataVizGUI.cpp(36): error C2664: 'std::basic_string<_Elem,_Traits,_Ax>::basic_string(const std::basic_string<_Elem,_Traits,_Ax>::_Alloc &)' : cannot convert parameter 1 from 'LPTSTR * ' to 'const std::basic_string<_Elem,_Traits,_Ax>::_Alloc &'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>,
            _Ax=std::allocator<char>
        ]
        and
        [
            _Elem=char,
            _Traits=std::char_traits<char>,
            _Ax=std::allocator<char>
        ]

Please provide me some sample code to convert the char*/LPTSTR* to STL string.

Thanks in advance,
Pampa
0
Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 
LVL 44

Expert Comment

by:Karl Heinz Kremer
ID: 10822441
This works for me:

            LPTSTR lptstr = "this is the lptstr";
            string the_string(lptstr);

            cout << the_string << endl;
0
 
LVL 44

Expert Comment

by:Karl Heinz Kremer
ID: 10822449
If this still does not help, show your source code.
0
 
LVL 16

Expert Comment

by:nonubik
ID: 10822576
Try this:

for(int i=0;i<nArgs;i++)
{
  if(!i)
    the_string +=' ';
  the_string += szArglist[i];
}

if you want all arguments to be palced in a string.
0
 
LVL 16

Expert Comment

by:nonubik
ID: 10822577
...my mistake, if(!i) should be if(i)
0
 
LVL 14

Expert Comment

by:wayside
ID: 10822627
> string stlStr ( szArglist ) ;

LPTSTR * is not the same as LPTSTR. The first is an array of pointers, the second is one pointer.

Since szArglist is an array of pointers, you would need to do

string stlStr1(szArglist[0]);
string stlStr2(szArglist[1]);

etc.
0
 
LVL 11

Expert Comment

by:cup
ID: 10822810
If you are using unicode, use wstring instead of string
0
 
LVL 10

Expert Comment

by:Sys_Prog
ID: 10822861
wayside is absolutely correct
All of us didn't notice that ur szArglist is a pointer of type LPTSTR

Amit

0
 
LVL 16

Expert Comment

by:nonubik
ID: 10822889
I did ;)
0
 
LVL 10

Expert Comment

by:Sys_Prog
ID: 10822934
Sorry nonubik,

I should have had a meticulous look at your code

Amit
0
 
LVL 16

Expert Comment

by:nonubik
ID: 10822964
np, maybe it was too obscure.
0
 

Author Comment

by:pampa_analytica
ID: 10830040
Hi guys,

int WINAPI WinMain(HINSTANCE hInstance,
                       HINSTANCE hPrevInstance,
                       LPSTR lpCmdLine,
                       int nCmdShow)
{
     LPTSTR *szArglist;
     int nArgs;
     szArglist = CommandLineToArgvW(GetCommandLineW(), &nArgs);
     string the_string;
//I would like to convert the szArglist to STL string object. I tried this:
          for( i=1; i<=nArgs-1; i++)
          {
      the_string = the_string + szArglist[i];
      MessageBox(NULL,szArglist[i],0,0);
         }
}

But i got this error:
f:\Viz\Viz_src\DataVizGUI\DataVizGUI.cpp(63): error C2678: binary '+' : no operator found which takes a left-hand operand of type 'std::string' (or there is no acceptable conversion).

I am unable to solve this coz I am pretty new to VC++. PLease help me out in solving this problem.



Thanks in advance,
Pampa
0
 
LVL 10

Expert Comment

by:Sys_Prog
ID: 10830058
pampa_analytica,

std::string does have a binary + operator
and the above code works fine for me

Amit
0
 

Author Comment

by:pampa_analytica
ID: 10830078
I got this error while I was trying to do this:
      for( i=1; i<=nArgs-1; i++)
      {
                  the_string += szArglist[i];
              MessageBox(NULL,szArglist[i],0,0);
      }


f:\Viz\Viz_src\DataVizGUI\DataVizGUI.cpp(64): error C2679: binary '+=' : no operator found which takes a right-hand operand of type 'LPTSTR' (or there is no acceptable conversion)
0
 

Author Comment

by:pampa_analytica
ID: 10830080
#include <string>
using namespace std;

These are my includes in the project
0
 
LVL 10

Expert Comment

by:Sys_Prog
ID: 10830127
I think u are using VC++6.0
But I tried on it & it works fine for me

Amit
0
 

Author Comment

by:pampa_analytica
ID: 10830157
No Amit I am using VC++7.0. I tried but still Iam getting the same error.
0
 
LVL 10

Accepted Solution

by:
Sys_Prog earned 50 total points
ID: 10830177
I am not sure but I have heard that VC++7.0 is less compliant compiler as compared to VC++7.1
I am not sure since I haven't used both
However, the code should work
The std::string does have a += as well as a + operator defined
Here is the quick reference

http://www.cppreference.com/cppstring_details.html#Operators

Amit

0
 
LVL 16

Expert Comment

by:nonubik
ID: 10830883
try a cast:
the_string += (char *)szArglist[i];
0

Featured Post

Networking for the Cloud Era

Join Microsoft and Riverbed for a discussion and demonstration of enhancements to SteelConnect:
-One-click orchestration and cloud connectivity in Azure environments
-Tight integration of SD-WAN and WAN optimization capabilities
-Scalability and resiliency equal to a data center

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

In days of old, returning something by value from a function in C++ was necessarily avoided because it would, invariably, involve one or even two copies of the object being created and potentially costly calls to a copy-constructor and destructor. A…
What is C++ STL?: STL stands for Standard Template Library and is a part of standard C++ libraries. It contains many useful data structures (containers) and algorithms, which can spare you a lot of the time. Today we will look at the STL Vector. …
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…
The viewer will be introduced to the member functions push_back and pop_back of the vector class. The video will teach the difference between the two as well as how to use each one along with its functionality.

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question