Q198953: HOWTO: Expand An Array Pointer in the Visual C++ Debugger

Article: Q198953
Product(s): Microsoft C Compiler
Version(s): winnt:6.0
Operating System(s): 
Keyword(s): kbDebug kbide kbVC600
Last Modified: 07-MAY-2001

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The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SUMMARY
=======

Starting with Visual C++ version 6.0, it is now possible to expand an array
pointer to view all array elements in the Visual C++ Debugger Watch window. This
feature is not documented.

In the Watch window, type an expression that evaluates to a pointer followed by a
comma and the number of elements in the array.

MORE INFORMATION
================

1. Build the debug version of the following code as a console application.

     // Filename main.cpp
     // No compile option needed

     #include <iostream.h>

     void main(void)
     {
       int * p;
       char* ptr = "Hello World";
       p = new int [10];

       for(int i=0; i<=9; i++){*(p+i) = i+1;}
       cout << i <<endl;
     }

2. Step into the code with the debugger and stop at the last line of code.

3. In the Watch or Quickwatch window, add the variable "p" (without the
  quotation marks) or "ptr" (without the quotation marks). You will see a '+'
  symbol next to the variable.

4. Click the '+' symbol to expand the variable. You will see only the first
  element of the array to which it points.

5. Now, type "p,10" (without the quotation marks) or "ptr,11" (without the
  quotation marks) in the Watch window.

6. Click the '+' symbol to expand the variable. Now you see all elements of the
  array to which it points.

If you want to see a specific range of elements, then enter the address of the
first element to specify the starting index, followed by the format specifier as
described in the preceding steps. For example, "(p+3),8" (without the quotation
marks) shows elements p[3..10], and "(ptr+3),10" (without the quotation marks)
shows elements ptr[3..12]. Unfortunately, the starting index in the Watch window
will be [0], which actually corresponds to index 3 in this example. You have to
remember that the offset 3 has to be added to each displayed index to get the
actual index of the array element.

Additional query words: kbDSupport

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Keywords          : kbDebug kbide kbVC600 
Technology        : kbVCsearch kbAudDeveloper kbVC600 kbVC32bitSearch
Version           : winnt:6.0
Issue type        : kbhowto

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