how to "new" a two-dimension array in C++?

[James]

Hi,

I want to directly create a dynamic two-dimension double array, i.e.
double pp[][]. I found the "new" is only for one-dimension array, i.e.
double *p = new p[dynamic_size]. How to "new" a two-dimension array?
Is the only way to create a class?

In java, I can easily create a two-dimension array by "double[][] pp =
new double[dynamic_size][dynamic_size]". But, how to do it in C++?

Looking forward to hearing from you!

Regards,

James

 

[Joona I Palaste]

Hi,

I want to directly create a dynamic two-dimension double array, i.e.
double pp[][]. I found the "new" is only for one-dimension array, i.e.
double *p = new p[dynamic_size]. How to "new" a two-dimension array?
Is the only way to create a class?

In java, I can easily create a two-dimension array by "double[][] pp =
new double[dynamic_size][dynamic_size]". But, how to do it in C++?

Looking forward to hearing from you!

Perhaps you should ask C++ questions in comp.lang.c++?

 

[Old Wolf]

In java, I can easily create a two-dimension array by "double[][] pp =
new double[dynamic_size][dynamic_size]". But, how to do it in C++?

In C (as well as C++) you must know all, or all-but-one,
of an array's dimensions at compile time.

In C you should create a one-dimensional array with malloc()
and then you can use macros to refer to it as if it were 2-d.

In C++ there are other solutions, you should post to comp.lang.c++
to get answers on that.

 

[E. Robert Tisdale]

I want to directly create a dynamic two-dimension double array, i.e.

double pp[][];

I found the "new" is only for one-dimension array, i.e.

double *p = new p[dynamic_size];

How to "new" a two-dimension array?
Is the only way to create a class?

In java, I can easily create a two-dimension array by

double[][] pp = new double[dynamic_size][dynamic_size];

But, how to do it in C++?
Looking forward to hearing from you!

Forget about new and try this:

double pp[dynamic_size][dynamic_size];

Variable length arrays are included in the C99 standard
and will be included in the new C++ standard.
Your compiler probably supports them already.