my string class

This is a discussion on my string class within the C++ Programming forums, part of the General Programming Boards category; I am trying to write my own string class but I have trouble writing: operator<< operator>> How do I access ...

  1. #1
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    my string class

    I am trying to write my own string class but I have trouble writing:
    operator<<
    operator>>
    How do I access ostream and istream?
    Please help?

  2. #2
    C++ Witch laserlight's Avatar
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    Declare them as friend functions of your class. The function prototypes might be like this:
    Code:
    std::ostream& operator<<(std::ostream&, const T&);
    std::istream& operator>>(std::istream&, T&);
    for some class T for which these are friend functions.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
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    thanx laserlight but it didnt really work, maybe you can explain it to me a little more

  4. #4
    Rabble Rouser Slacker's Avatar
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    The custom inserter and extractor can be as simple as this:
    Code:
    #include <iostream>
    #include <iomanip>
    #include <cstring>
    
    class String {
      char *mem;
      int size;
    public:
      String ( const char *p );
      ~String();
    
      friend std::istream& operator>> ( std::istream& is, String& s );
      friend std::ostream& operator<< ( std::ostream& os, const String& s );
    };
    
    String::String ( const char *p )
    {
      size = strlen ( p );
      mem = new char[size + 1];
      strcpy ( mem, p );
    }
    
    String::~String() { delete [] mem; }
    
    std::istream& operator>> ( std::istream& is, String& s )
    {
      return is.getline ( s.mem, s.size );
    }
    
    std::ostream& operator<< ( std::ostream& os, const String& s )
    {
      return os << s.mem;
    }
    
    int main()
    {
      String s = "My cool string";
    
      std::cout << s << "\nEnter a string: ";
      std::cin >> s;
      std::cout << s << '\n';
    }
    Last edited by Slacker; 12-26-2005 at 12:36 PM.

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