how to i made a full copy of a char pointer?

This is a discussion on how to i made a full copy of a char pointer? within the C++ Programming forums, part of the General Programming Boards category; Hi, I am a newbie. i would like to copy a string1 = " hello world " to char* buffer. ...

  1. #1
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    how to i made a full copy of a char pointer?

    Hi,

    I am a newbie.

    i would like to copy a string1 = " hello world "
    to
    char* buffer.

    This buffer is part of a class that i have created. the string1 is a parameter that will be sent into my constructor as a parameter.

    Hope i paint out my problem clearly.

    Thanks in advance!

  2. #2
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    Are you talking about the string class or an array of chars?

  3. #3
    & the hat of GPL slaying Thantos's Avatar
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    Code:
    Class::Class(char *src)
    {
      char* buffer new[strlen(src)+1];
      strcpy(buffer, src);
    }
    There are other ways of course. *cues the host of other posts showing other methods*

  4. #4
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    If the char array is null terminated, then the strcpy method will work. If you have a string that is not null-terminated(for instance like the char array returned for a REG_MULTI_SZ from the registry), you can use strncpy(dest, source, size). This will allow you to copy data that exists beyond the null terminator.

  5. #5
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    i would like to copy a string1 = " hello world "
    to
    char* buffer.

    Hope i paint out my problem clearly.
    Nope. You didn't say what type string1 is.

  6. #6
    Registered User major_small's Avatar
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    /me adds to thantos' program

    Code:
    Class::Class(char *src)
    {
      char* buffer new[strlen(src)+1];
      strcpy(buffer, src);
    }
    Class::Class(std::string src)
    {
      char* buffer new[src.length()+1];
      strcpy(buffer, src.c_str());
    }
    edit, yeah, I'm not actually sure if that works (no access to a compiler)... but the logic's there
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    Thantos has solved my problem. Thanks a lot!
    and thanks to everyone

  8. #8
    & the hat of GPL slaying Thantos's Avatar
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    Quote Originally Posted by mercury529
    If the char array is null terminated, then the strcpy method will work. If you have a string that is not null-terminated(for instance like the char array returned for a REG_MULTI_SZ from the registry), you can use strncpy(dest, source, size). This will allow you to copy data that exists beyond the null terminator.
    Well if the only parameter is the pointer you have to assume that it uses some character to mark the end. If they had said the length was passed also I would have used strncpy.

  9. #9
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    Quote Originally Posted by Thantos
    Well if the only parameter is the pointer you have to assume that it uses some character to mark the end. If they had said the length was passed also I would have used strncpy.
    Oh just giving them additional information for if they ever deal with non-null terminated char arrays which occasionally come into play.

  10. #10
    the hat of redundancy hat nvoigt's Avatar
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    I'm not sure if it's strictly ANSI, but at least on MS compilers there is a standard function called _strdup which accepts a char pointer and returns a new pointer to a new chuck of memory containing a copy of your original string. Only works with regular zero terminated character arrays.
    hth
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