Convert char to float

[Sastra Wijaya STMA]

I need to know how to convert a char variable into a float. The problem 
arises from calculating the elapsed time. First I get dosstampped of the
beginning process and the end process. The time I got from _dos_gettime(&tm), 
the variable tm is a struct of char.

What I did is:

elapsed = (tm2.hour-tm.hour)*3600+(tm2.minute-tm.minute)*60+(tm2.second-tm.second) + (tm2.hsecond-tm.hsecond)/100;

I use MSC 5.10  


Thanks for all your help,

Best Regard,

Sastra,