How can I get a float value from the comand line?

Hello all. Would you guys help a poor and tired student with an idea or point him to the right dirrection?

int main(int argc, char *argv[])

i do c++ in LINUX. i have a comand line which looks like this

myprog -a[0.2] -b[0.04] ....

I need to extract values in between brackets and saved them into the coresponding float variables. I can point to the number, but then?

float a, b ....

uhm. how can I convert a char into float? any easy way? any libraries that do that?

or suppose I have *p="0.01";
how can i turn this into float and save it to 'a'?

Thanks a lot

atof() or scanf()

strtod, sscanf