std::string and memory

This is a discussion on std::string and memory within the C++ Programming forums, part of the General Programming Boards category; How do I do memcpy with std::string? I tried: Code: std::string test; test.append(); But it doesnt work.. I want to ...

  1. #1
    l2u
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    std::string and memory

    How do I do memcpy with std::string?
    I tried:

    Code:
    std::string test;
    test.append();
    But it doesnt work..

    I want to do something like:

    Code:
    char h[4];
    size_t size = 12;
    memcpy(&h, &size, 4 );

  2. #2
    The larch
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    Append reference

    Basically append takes parameters to know what to append.

  3. #3
    l2u
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    Quote Originally Posted by anon
    Append reference

    Basically append takes parameters to know what to append.
    I did:
    string.append(&h, 0, 4);

  4. #4
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    You need to use pointers to the first and last element of the range. The name of an array acts like a pointer to the first element of an array, so 'h' is a pointer. On the other hand, something like h[3] is a character. However, you can use pointer arithmetic to get a pointer to h[3].
    Code:
    char h[] = "cruel world";
    
    string str = "hello";
    str.append(h+4, h+10);
    cout<<str<<endl;
    Or, if you want to append the whole char array, you can simply do this:
    Code:
    char h[] = "cruel world";
    
    string str = "hello ";
    str.append(h, 12);
    cout<<str<<endl;
    Last edited by 7stud; 01-17-2007 at 09:49 AM.

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