what is float** temp ?

[teslaa]

what is this variable with a double asterix?

float** temp;

temp = = new float*[l];

and whats that being assigned to it please?

[jsmith]

temp is a pointer-to-a-pointer-to-a-float.

In this case, temp is being treated by the programmer as an array of pointers to floats.
The line

temp = new float*[l];

is dynamically allocating an array of "l" pointers to floats.