#CB2240 Week9 classwork
#Tse Tsz Wong
#57153200

#Example A
def main():
    firstPart()
    secondPart()

def firstPart():
    print("FirstPart")

def secondPart():
    print("Second Part")

main()

#Example 2
def main1():
    print(plus_minus(15))

def plus_minus(x):
    return[x-1,x,x+1]

main1()

#Example 3:List Comprehension
lst1=[1.2,2.5,3.5,4.6]
print(lst1)

lst2=[int(x)for x in lst1]
print(lst2)

lst3=[x+2 for x in lst1]
print(lst3)

lst4=[x+2 for x in lst1 if x>=4]
print(lst4)

lst5=[2,3,4,5,6,7]
print(lst5)
lst6=[x*2 for x in lst5 if int(x)%2==1]
print(lst6)

#Example 4
lst=[i*2 for i in range(5)]
print(lst)

def presentValue(c,r,n):
    return round(sum([c/(1+r)**i for i in range(1,n+1)]),2)

print(presentValue(1000,0.05,6))

def differnce(x,y):
    return x-y

print(differnce(2,3))
print(differnce(3,2))

#Classwork9

def mainc():
    print(recur_sum([2,3,7,9]))
    input("\nPress Enter to exit.")

def recur_sum(lst):
    if len(lst)==0:
        print("ZERO")
        return 0
    else:
        print(lst[1:])
        return lst[0]+recur_sum(lst[1:])

mainc()