Thread: Converting int to const char* ?

  1. #1
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    Converting int to const char* ?

    How do I do this in c++?

    It's driving me crazy.

    thanks

  2. #2
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    Can you give more information on exactly what you're trying to do? Maybe an example?

    At first glance I'd say you'd use a stringstream (or boost's lexical_cast if you have boost).

  3. #3
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    How do you use a stringstream?

    I using some opencv function which takes a const char*, and I need to make the const char*'s I give it dynamic, hence I'm incrementing an int and converting to a const char*.

  4. #4
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    You can search for more examples and instructions:
    Code:
    #include <sstream>
    
    // ...
    
    void func(const char*);
    
    // ...
    
    int your_int = 33;
    std::ostringstream ostr;
    ostr << your_int;
    func(ostr.str().c_str());
    The str() returns a C++ string, and then c_str() is called on that string to return a const char*.

  5. #5
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    thanks, will try that in a sec

  6. #6
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    Quote Originally Posted by Daved View Post
    The str() returns a C++ string, and then c_str() is called on that string to return a const char*.
    Bear in mind that the pointer is only valid as long as the stringstream exists. If you need it longer than that, you need to make a copy somehow.

  7. #7
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    How can I do the following?

    ostr << "a" + i + ".jpg" ;

    where i is an int

    error C2110: '+' : cannot add two pointers
    Last edited by Wiretron; 11-12-2007 at 02:25 PM.

  8. #8
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    Use << instead of +.

    It works like you were outputting those things to cout. You would use << there as well.

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