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arraysdebuggingvisual-c++
yomismo
yomismo

Reputation: 11

view multi-dimensional array values debugging in Visual C++

I'm trying to debug some C++ code but I can't see the values in a multi-dimensional array while debugging

I have a dynamically allocated pointer (double **A).

When I try to watch the value of this array I just get the first value, I can't see the remaining values.

Any ideas?

TIA

Upvotes: 1

Views: 6772

Answers (5)

neuromouse
neuromouse

Reputation: 941

If you are using Visual Studio, put array[X],Y in the watch window, where X is the line number and Y the number of rows - this will allow you to watch whole lines in the watch window.

For example, put those lines to the watch window:

array[0],7
array[1],7
array[2],7
...

Upvotes: 3

user189040
user189040

Reputation:

This is what I get: http://www.flickr.com/photos/42475383@N03/4247049191/

edit.

I was using a CLR console project. I tried a win32 console and it works fine. I can see a google moment coming up to find out what a CLR project is.

Upvotes: 0

Yaakov Shoham
Yaakov Shoham

Reputation: 10548

Through the debugger you may write explicitly in the watch window A[2][1] etc..

Edited - after the code presented:

int main() {
    double **A; 
    double M = 4;
    A = new double *[M]; //define M by M matrix
    for( int k =0; k < M; k++) { 
        A[k] = new double [M]; 
    } 
    //assign values to matrix 
    for (int i = 0; i < M; i++) { 
        for (int j = 0; j < M; j++) { 
            if ( j == i) { 
                A[i][j] = 2; 
            } else { 
                A[i][j] = 1; 
            }
        }
    }
    return 0;
}

I put break point on the return 0 and add some test values to the watch window: 

    A[0][0] 2.0000000000000000  double
    A[0][1] 1.0000000000000000  double
    A[0][2] 1.0000000000000000  double
    A[1][0] 1.0000000000000000  double
    A[1][1] 2.0000000000000000  double
    A[1][2] 1.0000000000000000  double

It seems fine. What do you get when you're doing the same? Where is the problem? You can also print the values to screen as MatrixFrog suggested.

Upvotes: 0

Die in Sente
Die in Sente

Reputation: 9937

The simplest way to see large data arrays in VS is to use a memory window instead of a Watch window or the Autos or Locals window. Just drag your pointer value to the memory window's address box.

Upvotes: 6

Tyler
Tyler

Reputation: 22116

Iterate through and print out each value. Roughly something like this:

void print2DArray(double **A, int width, int height) {
    for (int i=0; i<width; i++) {
        for (int j=0; j<height; j++) {
            cout<<A[i][j]<<" ";
        }
        cout<<endl;
    }
}

Upvotes: 0

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