New with placement should be as simple as follows. First, use
'new (arena) TYPE[INDEX];' , second, don't use delete on it.
In this case you use the arena as float, so just don't delete it.
If you want to use the arena as class object, you should use explicit
destructor.
Masaharu Goto
#include <stdio.h>
main()
{
float *test[10000][1000];
for(int i=0;i<10000;i++)
for(int ii=0;ii<1000;ii++)
{ test[i][ii] = new (arena) float[10000];
for(int j=0;j<10000;j++)
test[i][ii][j] = i*j;
}
}