How to code my get number float at Epitech (require my_get_number or atoi and my_power_rec or my_power_it or pow)

my_get_nbr_float pseudo-code

integer = my_getnbr(str)
str = str after the '.' character
decimal = my_getnbr(str)
decimal = decimal / 10^(strlen(str)) * (1 if number is strictly positive, -1 else)
number = integer + decimal

example:
[line] [values]
[1] str = '-13.04' integer = -13
[2] str =     '04' integer = -13
[3] str =     '04' integer = -13 decimal = 4
[4] str =     '04' integer = -13 decimal = 4 / 10^2 * -1 = 4 / 100 * -1 = -0.04
[5] str =     '04' integer = -13 decimal = -0.04 number = -13 + -0.04 = -13.04
number = -13.04