Couple questions

This is a discussion on Couple questions within the C++ Programming forums, part of the General Programming Boards category; I searched the web for these, but couldn't find anything. 1) How do you find a file's extention (type)? 2) ...

  1. #1
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    Couple questions

    I searched the web for these, but couldn't find anything.

    1) How do you find a file's extention (type)?
    2) How do you link strings together in one variable or string?
    (eg. newstring = oldstring1 + oldsting2 [is it even possible?])

  2. #2
    aoeuhtns
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    In C++, you can do #2 with the std::string datatype.

    For #1, just start at the end of a filename string and step back until you get a fullstop or the beginning of the string.

  3. #3
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    Code:
    #include <iostream>
    #include <string>
    
    using namespace std;
    
    int main()
    {
         string s1 = ("hello");
         string s2 = ("world");
         string s3 = s1 + " " + s2 + "!";
         cout << s3 << endl;
         cin.get();
         return 0;
    }

  4. #4
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    I found strcat() to solve my problem.

  5. #5
    and the hat of wrongness Salem's Avatar
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    > I found strcat() to solve my problem.
    Then you're not really using C++ to it's best advantage - check ILoveVectors post.

    > 1) How do you find a file's extention (type)?
    Find the last '.' in the filename?
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  6. #6
    dra
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    >1) How do you find a file's extention (type)?

    something like this

    Code:
    #include <iostream>
    #include <string>
    
    using namespace std;
    
    int main(){
    
                 string filename = "blah.mp3";
    
                 string::iterator i = filename.end();
    
                 while ( *i != '.' ){
    
                           i--;
    
                 }
    
                 cout << "The extension is " << string( i, filename.end() );
    
                 return 0;
    
         }
    Last edited by dra; 08-19-2005 at 02:24 AM.

  7. #7
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    dra, your code derefences the invalid iterator returned by end(). You would want to decrement it first. Also, you should use rfind() instead of your own hand-written loop to avoid small mistakes like that.

  8. #8
    dra
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    oh. lol okay thanks.
    Last edited by dra; 08-19-2005 at 07:37 PM.

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