#!/usr/local/bin/python3

# filename: port_of_second_program.py
# rev. date/time: 03-28-13-0825 hrs.
# by Mr. Cantlin.

# Line 1 above is traditionally called a "shebang" line in Python.
# The #! symbols are the reason for the name.
# The # does not start a comment line in this first line.
# There should be no white space in the shebang line.
# The shebang tells the OS where to find the Python files.
# It tells Linux to look at the $PATH environmental variable
# for the location of the Python.exe program.
# It may not be needed if your OS is Windows.
# It is not needed when you are running programs from IDLE.

# **IDLE is set to reformat paragraphs after 70 characters per line**.

# Python really thinks indents are important.
# Indented modules must be tabbed or indented 4 spaces.
# Thou shall not indent three, or two, except when passing to 4.
# Clearly derived from the Holy Hand Grenade :-)

# ****************************************************
# Description of Program:
# Write a program that will add two or more vectors
# when the vectors are given in polar form.
# Reference: Page 236 Problem 76.

# This Python program is a port of a Javascript program
# that I wrote earlier as a demo for Dalton - Mr. Cantlin.
# Spring Break 2013.
# ****************************************************

# ****************************************************
# A pair of vectors to use for testing. See Ex. 3 Pg. 230
# Vector 1 = (13.8, 40.2 degrees)
# Vector 2 = (20.9, 164.6 degrees)
# Resultant Vector - Rectangular Form = (-9.6, 14.5)
# Resultant Vector - Polar Form = (17.4, 123.6 degrees)
# All text references are from "Trigonometry with Applications"
# By Wesner and Mahler, 3rd Ed. 1994, ISBN 0-697-12292-1
# ****************************************************

# ****************************************************
# Define and initialize variables.
# Use 0.0 to define as Floating Point. No EOL ";" of course.
# The "var" keyword is not used either.
vector1_magnitude = 0.0
vector1_angle = 0.0
vector2_magnitude = 0.0
vector2_angle = 0.0
vector1_x = 0.0
vector1_y = 0.0
vector2_x = 0.0
vector2_y = 0.0
vector_sum_x = 0.0
vector_sum_y = 0.0
vector_sum_magnitude = 0.0
vector_sum_angle = 0.0
# ****************************************************

# ****************************************************
# Prompt for user input.
# The input is converted to floating point in the same step.
# Default ending to print() is end='\n' i.e. one new line.
# Use end='\n\n' for two new line or end=" " for no new line.
print("Add Two Vectors in Polar Form", end='\n\n')
vector1_magnitude = float(input("Enter Vector 1 Magnitude: "))
vector1_angle = float(input("Enter Vector 1 Angle (Degrees): "))
vector2_magnitude = float(input("Enter Vector 2 Magnitude: "))
vector2_angle = float(input("Enter Vector 2 Angle (Degrees): "))
# ****************************************************

# ****************************************************
# Find the x and y components of the input vectors
# Since the math function works only in radians
# convert degrees to radians by multiplying by pi/180
# Python Gotcha, before you use any math() function,
# you have to import the math module :-(.
import math    # import the math function before first use of it.
vector1_x = vector1_magnitude * math.cos(vector1_angle*math.pi/180)
vector2_x = vector2_magnitude * math.cos(vector2_angle*math.pi/180)
vector1_y = vector1_magnitude * math.sin(vector1_angle*math.pi/180)
vector2_y = vector2_magnitude * math.sin(vector2_angle*math.pi/180)
# ****************************************************

# ****************************************************
# Add the x components and y components to get the
# sum of the vectors in rectangular form.
vector_sum_x = vector1_x + vector2_x
vector_sum_y = vector1_y + vector2_y
# ****************************************************

# ****************************************************
# Convert the vector sum from rectangular to polar form.
# Use the atan2(y,x) function to ensure the angle returned
# is in the proper Quadrant. Warning-two arguments: y is first!
vector_sum_magnitude = math.sqrt(math.pow(vector_sum_x,2)+math.pow(vector_sum_y,2))
vector_sum_angle = math.atan2(vector_sum_y,vector_sum_x)
vector_sum_angle = vector_sum_angle * (180/math.pi)
# ****************************************************

# ****************************************************
# Display Results
print("", end='\n\n') # skip two lines
print("*****************************")
print("Results: ")
print("Vector 1 Magnitude: ",vector1_magnitude)
print("Vector 1 Angle (Degrees): ",vector1_angle, end='\n')
print("Vector 2 Magnitude: ",vector2_magnitude)
print("Vector 2 Angle (Degrees): ",vector2_angle, end='\n\n')
print("Vector Sum in Rectangular Form: ","(",vector_sum_x,",",vector_sum_y,")",end='\n\n')
print("Vector Sum in Polar Form: ","(",vector_sum_magnitude,",",vector_sum_angle,"degrees",")",end='\n\n')
print("*****************************")
# ****************************************************