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  4. Delete [] charPtr... Pls help

Delete [] charPtr... Pls help

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  • C c121hains

    When I attach the CStrings together (newString = string[0] + string[1] + string[2] ..), the result does not correctly append the strings. My strings contain '\n' and '\r' characters and it seems that when I use the newString += string, only the first result is copied. Here is an example: string1 = "this is a string \r\n"; string2 = "this is an appended string \r\n"; string1 += string2; string1 still equals "this is a string \r\n" and doesn't append string2!! I need those '\r' and '\n' characters. By putting them all into a char string, it fixes this problem.

    D Offline
    D Offline
    David Crow
    wrote on last edited by
    #8

    c121hains wrote: ...and doesn't append string2!! How do you know?


    "Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

    C 1 Reply Last reply
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    • C c121hains

      I tried that but it didn't work. Here is an example of what happens: string1 = "this is a string \r\n"; string2 = "this is an appended string \r\n"; string1 += string2; string1 still equals "this is a string \r\n" and doesn't append string2!! I need those '\r' and '\n' characters. By putting them all into a char string, it fixes this problem.

      M Offline
      M Offline
      Michael Dunn
      wrote on last edited by
      #9

      c121hains wrote: string1 still equals "this is a string \r\n" and doesn't append string2 How are you determining this? --Mike-- Visual C++ MVP :cool: LINKS~! Ericahist | 1ClickPicGrabber | CP SearchBar v2.0.2 | C++ Forum FAQ Come quietly or there will be... trouble.

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      • C c121hains

        All i want to do is get all of the text together from an array of CString objects and put it into a single char* pointing to a string. I'm doing memory allocation and I can't find away to delete the original temp data. It works, but..."I'm stomping on other memory!" :wtf: This should be the easiest thing ever. But i'm worried about a memory leak here. Whenever I try to delete allText before creating a NEW allText allocation, it dies. Any ideas how to fix these memory leaks? char* CFindInWindowDlg::GetTextLinesBuffer() { char* allText = NULL; char* source = NULL; int sizeAllText = 0; if (numLines > 0) { // **** 'lines' is my array of CString objects!!! int sizeAllText = strlen(lines[0].GetBuffer(0)); source = new char[sizeAllText]; strcpy(source, lines[0].GetBuffer(0)); for (int a = 1; a < numLines; a++) { // **** 'lines' is my array of CString objects!!! sizeAllText = MergeLines(&allText, sizeAllText, &source, lines[a].GetBuffer(0)); source = allText; } } return allText; } int CFindInWindowDlg::MergeLines(char** allText, int sizeSource, char** source, char* aLine) { int newSize; if ((sizeSource == 0) && (*source == NULL)) { *allText = new char[strlen(aLine)]; newSize = strlen(aLine); strcpy(*allText, aLine); return newSize; } newSize = sizeSource + strlen(aLine); *allText = new char[newSize]; strcpy(*allText, *source); strcat(*allText, aLine); return newSize; }

        J Offline
        J Offline
        Jose Lamas Rios
        wrote on last edited by
        #10

        c121hains wrote: All i want to do is get all of the text together from an array of CString objects and put it into a single char* pointing to a string. Try this:

        void MergeLines(const CString* lines, int nLines, CString& result)
        {
           // Get total length
           int nTotalLength = 1; // at least a null terminator will be needed
           for (int i = 0; i < nLines; i++)
              nTotalLength += lines[i].GetLength();
         
           result.Empty();
         
           // Avoid re-allocating and copying in each iteration
           result.GetBuffer(nTotalLength);
           result.ReleaseBuffer();
         
           // Concatenate all strings into result
           for (int i = 0; i < nLines; i++)
              result += lines[i];
        }

        Disclaimer: I didn't compile it. May contain some error[s]. -- jlr http://jlamas.blogspot.com/[^]

        C 1 Reply Last reply
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        • M Michael Dunn

          c121hains wrote: string1 still equals "this is a string \r\n" and doesn't append string2 How are you determining this? --Mike-- Visual C++ MVP :cool: LINKS~! Ericahist | 1ClickPicGrabber | CP SearchBar v2.0.2 | C++ Forum FAQ Come quietly or there will be... trouble.

          C Offline
          C Offline
          c121hains
          wrote on last edited by
          #11

          In the debugger.. There is no change to the original string: originalString = "the original string \r\n"; originalString += "a new string \r\n"; ------ originalString still equals "the original string \r\n"; Do you get a different result?

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          • C c121hains

            In the debugger.. There is no change to the original string: originalString = "the original string \r\n"; originalString += "a new string \r\n"; ------ originalString still equals "the original string \r\n"; Do you get a different result?

            J Offline
            J Offline
            Jose Lamas Rios
            wrote on last edited by
            #12

            It should work. Maybe the debugger is showing only the first line. Try doing a TRACE() and see the result in the output window. -- jlr http://jlamas.blogspot.com/[^]

            C 1 Reply Last reply
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            • J Jose Lamas Rios

              c121hains wrote: All i want to do is get all of the text together from an array of CString objects and put it into a single char* pointing to a string. Try this:

              void MergeLines(const CString* lines, int nLines, CString& result)
              {
                 // Get total length
                 int nTotalLength = 1; // at least a null terminator will be needed
                 for (int i = 0; i < nLines; i++)
                    nTotalLength += lines[i].GetLength();
               
                 result.Empty();
               
                 // Avoid re-allocating and copying in each iteration
                 result.GetBuffer(nTotalLength);
                 result.ReleaseBuffer();
               
                 // Concatenate all strings into result
                 for (int i = 0; i < nLines; i++)
                    result += lines[i];
              }

              Disclaimer: I didn't compile it. May contain some error[s]. -- jlr http://jlamas.blogspot.com/[^]

              C Offline
              C Offline
              c121hains
              wrote on last edited by
              #13

              This works: char* CFindInWindowDlg::GetTextLinesBuffer() { CString allText = ""; for (int a = 0; a < numLines; a++) { allText += lines[a].GetBuffer(0); lines[a].ReleaseBuffer(); } return allText.GetBuffer(0); } Any idea why I need to use GetBuffer instead of string1 += string2?

              J 1 Reply Last reply
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              • J Jose Lamas Rios

                It should work. Maybe the debugger is showing only the first line. Try doing a TRACE() and see the result in the output window. -- jlr http://jlamas.blogspot.com/[^]

                C Offline
                C Offline
                c121hains
                wrote on last edited by
                #14

                This works: char* CFindInWindowDlg::GetTextLinesBuffer() { CString allText = ""; for (int a = 0; a < numLines; a++) { allText += lines[a].GetBuffer(0); lines[a].ReleaseBuffer(); } return allText.GetBuffer(0); } Any idea why I need to use GetBuffer instead of string1 += string2?

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                • D David Crow

                  c121hains wrote: ...and doesn't append string2!! How do you know?


                  "Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

                  C Offline
                  C Offline
                  c121hains
                  wrote on last edited by
                  #15

                  This works: char* CFindInWindowDlg::GetTextLinesBuffer() { CString allText = ""; for (int a = 0; a < numLines; a++) { allText += lines[a].GetBuffer(0); lines[a].ReleaseBuffer(); } return allText.GetBuffer(0); } Any idea why I need to use GetBuffer instead of string1 += string2?

                  J 1 Reply Last reply
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                  • M Michael Dunn

                    c121hains wrote: string1 still equals "this is a string \r\n" and doesn't append string2 How are you determining this? --Mike-- Visual C++ MVP :cool: LINKS~! Ericahist | 1ClickPicGrabber | CP SearchBar v2.0.2 | C++ Forum FAQ Come quietly or there will be... trouble.

                    C Offline
                    C Offline
                    c121hains
                    wrote on last edited by
                    #16

                    This works: char* CFindInWindowDlg::GetTextLinesBuffer() { CString allText = ""; for (int a = 0; a < numLines; a++) { allText += lines[a].GetBuffer(0); lines[a].ReleaseBuffer(); } return allText.GetBuffer(0); } Any idea why I need to use GetBuffer instead of string1 += string2?

                    M 1 Reply Last reply
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                    • C c121hains

                      This works: char* CFindInWindowDlg::GetTextLinesBuffer() { CString allText = ""; for (int a = 0; a < numLines; a++) { allText += lines[a].GetBuffer(0); lines[a].ReleaseBuffer(); } return allText.GetBuffer(0); } Any idea why I need to use GetBuffer instead of string1 += string2?

                      J Offline
                      J Offline
                      Jose Lamas Rios
                      wrote on last edited by
                      #17

                      c121hains wrote: This works: char* CFindInWindowDlg::GetTextLinesBuffer() { CString allText = ""; [...] return allText.GetBuffer(0); That may seem to work, but it actually doesn't. You can't return a pointer to the internal buffer in allText, since that variable will be destroyed as soon as the function terminates. Check the code I suggested in a previous post (the function receives a CString reference from the caller and stores the result in it). c121hains wrote: Any idea why I need to use GetBuffer instead of string1 += string2? You don't need to use GetBuffer; that's not the problem. -- jlr http://jlamas.blogspot.com/[^]

                      T 1 Reply Last reply
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                      • C c121hains

                        This works: char* CFindInWindowDlg::GetTextLinesBuffer() { CString allText = ""; for (int a = 0; a < numLines; a++) { allText += lines[a].GetBuffer(0); lines[a].ReleaseBuffer(); } return allText.GetBuffer(0); } Any idea why I need to use GetBuffer instead of string1 += string2?

                        J Offline
                        J Offline
                        Jose Lamas Rios
                        wrote on last edited by
                        #18

                        c121hains wrote: Any idea why I need to use GetBuffer instead of string1 += string2? Ok. I already answered this. :) Again, I suggest you try the implementation I posted before. -- jlr http://jlamas.blogspot.com/[^]

                        1 Reply Last reply
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                        • J Jose Lamas Rios

                          c121hains wrote: This works: char* CFindInWindowDlg::GetTextLinesBuffer() { CString allText = ""; [...] return allText.GetBuffer(0); That may seem to work, but it actually doesn't. You can't return a pointer to the internal buffer in allText, since that variable will be destroyed as soon as the function terminates. Check the code I suggested in a previous post (the function receives a CString reference from the caller and stores the result in it). c121hains wrote: Any idea why I need to use GetBuffer instead of string1 += string2? You don't need to use GetBuffer; that's not the problem. -- jlr http://jlamas.blogspot.com/[^]

                          T Offline
                          T Offline
                          Tim Smith
                          wrote on last edited by
                          #19

                          A classic case of "MFC must be broken because my code works just fine." Wrong. :) Tim Smith I'm going to patent thought. I have yet to see any prior art.

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                          • C c121hains

                            This works: char* CFindInWindowDlg::GetTextLinesBuffer() { CString allText = ""; for (int a = 0; a < numLines; a++) { allText += lines[a].GetBuffer(0); lines[a].ReleaseBuffer(); } return allText.GetBuffer(0); } Any idea why I need to use GetBuffer instead of string1 += string2?

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                            M Offline
                            Michael Dunn
                            wrote on last edited by
                            #20

                            Well, that only "works" by chance. You're returning a pointer to the local variable allText which immediately goes out of scope. --Mike-- Visual C++ MVP :cool: LINKS~! Ericahist | 1ClickPicGrabber | NEW~! CP SearchBar v3.0 | C++ Forum FAQ I even hear the Windows "OMG I booted up fine" sound.   -- Paul Watson diagnosing hardware problems.

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