Algorithm to count the digits in a given number?

Answer 1

def digits(x):
""" Return amount of digits of x. """
y = math.log10(x)
if y % 1 0:
return int(y)
else:
return int(math.floor(y) + 1)

Answer 2

for (revn=0; n!=0; n/=10) revn = 10*revn + n%10;