c++ newbie question: how to pass an array as an argument in a function template?

[Antst]

Hi everyone:

I am having trouble passing an array as an argument in a function template. I get this error: "does not match any template declaration". Can anyone suggest how to do this?

Here is what I have:

template <typename T>
void matrixCode(T** someMatrix)
{
// my code
}

I call it in main() as:

matrixCode( myMatrix )

Any advice would be much appreciated! Thanks.

 

[MichaelInScarborough]

Cubbie's answer are really exhausting the problem with these two minor exceptions, which would compile w/o problems.

template <typename T>
void matrixCode(T** someMatrix)
{
// my code
}

int main()
{
int *ptr = NULL;
matrixcode(&ptr);
double **pptr = NULL;
matrixcode(pptr);
return 0;
}

 

[Neebler]

The way you're calling the function, myMatrix would have to be declared like one of these:

double *myMatrix[3]; // array of 3 pointers to double
double **myMatrix; // pointer to pointer to double

If you declared it like

double myMatrix[3][3];

Then your T type will be interpreted as double*(myMatrix[3]), i.e. A pointer to an array of three doubles. The binary storage of this last declaration is nine double values, one after another. The binary storage that your template function is looking for is a pointer to an array of pointers to T.

You can redefine the template function like this:

template< typename T, int cols >
void matrixCode( T (*someMatrix)[ cols ] )
{
}