Exercise 17 : Function 1

Test :

1. DRY : Don’t Repeat Yourself.
2. The use of function :
   • To reduce the amount of code.
   • To make fixing the debug easier.
   • To make easier to read.

Try :

1. Use function to act as pow(a, b) = a**b

   def power(x, y):
       result = 1
       for i in range(y):
           result *= x
   
       return result
   
   print(power(3,5))

2. Greatest Common Divisor (gcd)

   gcd(x, y) = gcd(y, x mod y)

   Euclidean algorithm (辗转相除法)

   for example :

   168	63
   168	63	42	余数0
   63	42	21	gcd = 21
   2*63+ 42	42+21	2*42

   def gcd(x, y):
       while y:
           t = x%y
           x = y
           y = t
   
       return x
   
   x = int(input('Pls input an integer x:'))
   y = int(input('Pls input an integer y:'))
   print(gcd(x,y))

3. Turn decimal system to binary system.

   def DectoBin(dec):
       temp = [ ]
       result = ' '
   
       while dec:
           quo = dec % 2
           dec = dec // 2
           temp.append(quo)
   
       while temp:
           result += str(temp.pop())
   
       return result
   
   Dec = int(input('Pls input an integer:'))
   print('Bin =', DectoBin(Dec))