Differential between fruitful function and non-fruitful function

Fruitful Function: Function that returns a value

 def power(x,y):
   for i in range(y):
     r=r*x
   print(r)
 
 a=intinput((“Enter Base”))
 b=intinput((“Enter Exponent”))
 
 power(a,b) 

Non-Fruitful Function: Function that does not return any value.

 def power(x,y=3):
   for i in range(y):
     r=r*x
   return r
 
 a=intinput((“Enter Base”))
 b=intinput((“Enter Exponent”))
 
 total = power(a,b)
 print(total)