How do I clear a 2D or 3D array fast without loops ?

[make026]

Hello all!
I can clear a 1D array fast like this:

char a[10] = "";
int b[5] = {0};

But I don't know how to clear a 2D or 3D array fast without loops:
(I don't want to use a for-loop or while-loop...)

char a2D[10][5];
int b2D[5][5];

char a3D[10][5][5];
int b3D[5][5][5];

[Moschops]

char a2D[10][5];
memset(a2D, 0, 50);

int b2D[5][5];
memset(b2D, 0, 25*(sizeof(int));

int b3D[5][5][5];
memset(b3D, 0, 125*(sizeof(int));

[andywestken]

Or...

char a2D[10][5];
memset(a2D, 0, sizeof(a2D));

int b2D[5][5];
memset(a2D, 0, sizeof(b2D));

int b3D[5][5][5];
memset(b3D, 0, sizeof(b3D));

Though the following also work for declaration

char a2D[10][5] = {0};

int b2D[5][5] = {0};

int b3D[5][5][5]= {0};

But you still need the memset approach to reset the arrays back to zero.

Andy

PS (The following definitely holds for vc++, as is prob true for other compilers) If you set a breakpoint on a line like int b2D[5][5] = {0}; and look at the disassembly, you'll find it's calling memset in most cases. The exceptions seem to be very small structs, like class Point(int x; int y;}; where it just sets the two values to zero. So there's no performance difference between the two approaches for non-tiny arrays.

[make026]

Thank you, Moschops!!!
Thank you, andywestken!!!