#20th-25th November 2015
#Homework

#setting values of variables.
def abcdx():
    print "a - Square"
    print "b - Rectangle"
    print "c - Triangle"
    print "d - Circle"
    print "x - Exit"
#importing the function.
from math import pi
import sys

def chooseoperation(): #choosing which operation you want to use
    global choiceofoperation
    choiceofoperation = raw_input("Please tell me which operation you want to use.")
    choiceofoperation = choiceofoperation.lower()
#for working out the square
def square():
    print "You are working with a square"
    sidelength = float(raw_input("Please enter the length of a side of this square."))
    area = sidelength ** 2
    perimeter = sidelength * 4 #equation to figure out what you need
    print "The area of this square (with side length", str(sidelength) + ") is:", str(area), ", And the perimeter of this square is: ", str(perimeter)
#working out of a square using def to set its own variables
def rectangle():
    print "You are working with a rectangle"
    shortersidelength = float(raw_input("Please tell me the length of one of the two shorter sides."))
    longersidelength = float(raw_input("Please tell me the length of one of the two longer sides."))
    area = shortersidelength * longersidelength
    perimeter = (shortersidelength * 2) + (longersidelength * 2)
    print "The area of this rectangle (with shorter side length", str(shortersidelength) + ", and longer side length", str(longersidelength), "is:", str(area), "And the perimeter of this rectangle is:", str(perimeter)
#working out for a triangle.
def triangle():
    print "You are working with a triangle"
    longestlength = float(raw_input("Please tell me the length of the longest side of the triangle."))
    secondlongestlength = float(raw_input("Please tell me the length of the second longest side of the triangle."))
    thirdlongestlength = float(raw_input("Please tell me the length of the third longest (AKA shortest) side of the triangle."))
    area = (longestlength * secondlongestlength) / 2
    perimeter = longestlength + secondlongestlength + thirdlongestlength
    print "The area of this triangle (with longest length", str(longestlength) + ", second longest length", str(secondlongestlength), "and shortest length", str(thirdlongestlength) + "), is:", str(area), "And the perimeter of this triangle is:", str(perimeter)
def circle():
    print "You are working with a circle!"
    radius = float(raw_input("Please give me the radius of the circle."))
    area = pi * (radius ** 2)
    circumference = pi * (radius * 2)
    print "The area of this circle (with the radius", str(radius) + ") is:", str(area), "And the circumference of this circle is:", str(circumference)
def exit():
    print "Okay!"
    sys.exit()

while True:

    chooseoperation()

    while choiceofoperation not in ("a","b","c","d","x"):
        print "You did not make an acceptable choice."
        abcdx()
        chooseoperation()

    if choiceofoperation == "a":
        square()
    elif choiceofoperation == "b":
        rectangle()
    elif choiceofoperation == "c":
        triangle()
    elif choiceofoperation == "d":
        circle()
    elif choiceofoperation == "x":
        print "Okay, exiting!"
        sys.exit()