Copying character arrays

This is a discussion on Copying character arrays within the C++ Programming forums, part of the General Programming Boards category; I'm trying to make a simple binary search tree. Each node has a char data type, and a pointer to ...

  1. #1
    30 Helens Agree neandrake's Avatar
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    Copying character arrays

    I'm trying to make a simple binary search tree. Each node has a char data type, and a pointer to a char. For the tree class, this information needs to be filled in when inserting items. I am having troubles inserting the character array. Here is my class. I am trying to keep this simple, no complications needed.

    Code:
    #include <cstring>
    
    class bNode
    {
    	private:
    		char ch;
    		char *code;
    		bNode *left, *right;
    	public:
    		bNode() { ch = 0; }
    		~bNode() { delete code; }
    		char getCh() { return ch; }
    		char* getCode() { return code; }
    		void setCh(char c) { ch = c; }
    		void setCode(char *c)
    		{
    			code = new char[strlen(c)+1];
    			strcpy(code, c);
    		}
    };
    The program just crashes, and I've searched and found that the crash occurs on the call to setCode() for a node. Anyone know what I am doing wrong?
    Environment: OS X, GCC / G++
    Codes: Java, C#, C/C++
    AOL IM: neandrake, Email: neandrake (at) gmail (dot) com

  2. #2
    Sweet
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    Well you are going to want to first delete the memory in which you first allocated to code so i would delete [] code. But other than that I don't see why it is failing. What are you passing to it?
    Also i would set code to 0 when constucting your node.
    Not a huge deal also I would make
    Code:
    char* getCode() { return code; }
    Code:
    char* getCode() const { return code; }
    Last edited by prog-bman; 02-27-2005 at 04:56 PM.
    Woop?

  3. #3
    Registered User
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    inserting arrays wont wont work if you use ordinary delete.
    you must use delete [].

    you might need to set a flag wheter what youve inserted is an array or not and call the corresponding delete function in the destructor.
    signature under construction

  4. #4
    Sweet
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    Here let me re post what I meant.
    Code:
    void setCode(const char *c)//Make this const 
    {			
      delete [] code;//each time you were reassigning this you were creating a memory leak without delete
      code = new char[strlen(c)+1];
      strcpy(code, c);
    }
    Also in your constructor I would do this
    Code:
    bNode()
    {
       char = 0;
       code = 0;
    }
    And in the destuctor
    Code:
    ~bNode()
    {
      delete [] code;
    }
    I would also make your return c and code functions const.
    Code:
    char getCh() const { return ch; }
    char* getCode() const { return code; }
    One more thing
    Code:
    void setCh(const char c) { ch = c; }
    //make this parameter const as well
    Woop?

  5. #5
    30 Helens Agree neandrake's Avatar
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    Thank you, I've found the problem, it was because I needed delete at the beginning of the function (along with the extra []). I did take in to mind adding consts where needed, which I've started doing. Thanks again, now I just have to fix the other problems.
    Environment: OS X, GCC / G++
    Codes: Java, C#, C/C++
    AOL IM: neandrake, Email: neandrake (at) gmail (dot) com

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