Q:

Convert number in scientific notation string to float with limited C-like library

I'm writing a program in CAPL (which is based on C and minus some concepts) to convert a string containing a number displayed in scientific notation to a float (doesn't strictly need to be a float but I think its an appropriate type for this). For example: 

-7.68000000E-06 should be converted to -0.00000768

I've done some looking around for this and atof() comes up a lot but this is not supported in CAPL so I cannot use that. 
A list of the other C concepts not supported in CAPL:

Update: Thanks everyone for the help. M. Spiller's answer proved to be the easiest solution. I have accepted this answer.

A:

In CAPL the function is called atodbl with the same signature as C's atof.

