dear god PLEASE HELP!?! (python)

Comments

• infidel

  May 2006

  : [b][red]This message was edited by streak118 at 2006-5-1 0:1:14[/red][/b][hr]
  : ok... Im a tard... somebody, ANYBODY!, please help! tell me what I'm doing wrong? or better yet tell me what to fix and how to? this is a class project. I'm failing this class because Im not grasping programming... and I started with C++ then came to this, HELP!?!
  :
  : #This program will calculate the time it will take a sound to travel based on
  : #the matter it is traveling through; air, water, or steel.
  :
  : [code]
  : def main():
  :
  : #declare and initialize variables
  : #AIR as constant
  : AIR = 1100
  :
  : #WATER as constant
  : WATER = 4900
  :
  : #STEEL as constant
  : STEEL = 16400
  :
  : #MenuChoice as string
  : MenuChoice = " "
  :
  : #feet as int
  : #feet = 0
  :
  : #seconds as int
  : seconds = 0
  :
  : #Intro
  : print "WELCOME TO THE SPEED OF SOUND PROGRAM!!!"
  : print "I will calculate the time it takes for a souond to travel through"
  : print "different matter."
  :
  : #build menu for user to choose from
  : print "Please choose from the following menu:
  "
  :
  : print " A) Air"
  : print " W) Water"
  : print " S) Steel"
  :
  : #prompt user for MenuChoice
  : MenuChoice = raw_input("
  Please enter your choice here: ")
  :
  : #prompt user for distance of travel
  : feet = input("Now, please enter the distance that the sound wave will travel(feet): ")
  :
  : #calculate time for sound to travel
  : A = AIR
  : W = WATER
  : S = STEEL
  :
  : if MenuChoice == A:
  : seconds = feet / AIR
  : elif MenuChoice == W:
  : seconds = feet / WATER
  : else:
  : MenuChoice == S
  : seconds = feet / STEEL
  :
  : #display ETA of the sound
  :
  : print "
  It will take", seconds, "second(s) for the sound wave to travel."
  : [/code]
  
  I'll take a closer look a little later, but for now, one quick lesson in Python. The interpreter does not automatically call any "main" function. All you've done here is define a function named "main" and then everything ends. You need to put a call to main after you define it:
  
  [code]
  def main():
  blah blah blah...
  
  main()
  [/code]
  
  : ps... I have this indented but it's not showing up on the message board.
  
  You need to use the special formatting tags for this board system, [leftbr]code[rightbr] and [leftbr]/code[rightbr]
  
  
  [size=5][italic][blue][RED]i[/RED]nfidel[/blue][/italic][/size]
  
  [code]
  $ select * from users where clue > 0
  no rows returned
  [/code]
  
  
• infidel

  May 2006

  : def main():
  :
  : #declare and initialize variables
  
  technically you never "declare" variables in python, you just bind names to values.
  
  : #AIR as constant
  : AIR = 1100
  :
  : #WATER as constant
  : WATER = 4900
  :
  : #STEEL as constant
  : STEEL = 16400
  
  I'm sure you know by now, but these aren't true "constants". Python has no such construct.
  
  : #prompt user for distance of travel
  : feet = input("Now, please enter the distance that the sound wave will travel(feet): ")
  
  input() is risky because it tries to eval() whatever the user enters so can very easily trigger exceptions. Better to use raw_input and try to convert the value to a decimal.
  
  : #calculate time for sound to travel
  : A = AIR
  : W = WATER
  : S = STEEL
  
  All you've done here is make two names both equal the same value A and AIR are now both references to the same integer object.
  
  : if MenuChoice == A:
  : seconds = feet / AIR
  : elif MenuChoice == W:
  : seconds = feet / WATER
  : else:
  : MenuChoice == S
  : seconds = feet / STEEL
  
  The user entered strings, but here you're checking their input against the value of A. A is different than 'A' in Python.
  
  : #display ETA of the sound
  :
  : print "
  It will take", seconds, "second(s) for the sound wave to travel."
  
  Like I mentioned in the other reply, you need to call your main function after defining it.
  
  Ok, so here is what I have come up with:
  
  [code]
  #This program will calculate the time it will take a sound to travel based on
  #the matter it is traveling through; air, water, or steel.
  
  # sound propagation "constants"
  AIR = 1100
  WATER = 4900
  STEEL = 16400
  
  def main():
  
  #Intro
  print "WELCOME TO THE SPEED OF SOUND PROGRAM!!!"
  print "I will calculate the time it takes for a souond to travel through"
  print "different matter."
  
  #build menu for user to choose from
  print "Please choose from the following menu:
  "
  print " A) Air"
  print " W) Water"
  print " S) Steel"
  
  #prompt user for choice
  choice = ' '
  while choice not in 'AaWwSs':
  choice = raw_input("
  Please enter your choice here (A, W, S): ")
  
  #prompt user for distance of travel
  feet = float(
  raw_input("Please enter the distance (feet) that the sound wave will travel: ")
  )
  
  #calculate time for sound to travel
  seconds = 0
  if choice in 'Aa':
  seconds = feet / AIR
  elif choice in 'Ww':
  seconds = feet / WATER
  elif choice in 'Ss':
  seconds = feet / STEEL
  
  #display ETA of the sound
  print "
  It will take", seconds, "second(s) for the sound wave to travel."
  
  if __name__ == '__main__':
  main()
  [/code]
  
  
  [size=5][italic][blue][RED]i[/RED]nfidel[/blue][/italic][/size]
  
  [code]
  $ select * from users where clue > 0
  no rows returned
  [/code]
  
  
• streak118

  May 2006

  thank you so much for your help! unfortunantly the teacher never taught us the __whatever__ codes so if I used them it would look suspicious... lol... here's what I ended up with minus input validations..
  
  [code]
  #This program will calculate the time it will take a sound to travel based on
  #the matter it is traveling through; air, water, or steel.
  
  
  def main():
  
  #declare and initialize variables
  #AIR as constant
  AIR = 1100
  
  #WATER as constant
  WATER = 4900
  
  #STEEL as constant
  STEEL = 16400
  
  #MenuChoice as string
  MenuChoice = " "
  
  #feet as int
  #feet = 0
  
  #seconds as int
  seconds = 0
  
  #Intro
  print "WELCOME TO THE SPEED OF SOUND PROGRAM!!!"
  print "I will calculate the time it takes for a souond to travel through"
  print "different matter."
  
  #build menu for user to choose from
  print "Please choose from the following menu:
  "
  
  print " A) Air"
  print " W) Water"
  print " S) Steel"
  
  #prompt user for MenuChoice
  MenuChoice = raw_input("
  Please enter your choice here: ")
  
  #prompt user for distance of travel
  feet = input("Now, please enter the distance that the sound wave will travel(feet): ")
  
  feet = float(feet)
  
  #calculate time for sound to travel
  
  if MenuChoice == "A":
  seconds = feet / AIR
  elif MenuChoice == "W":
  seconds = feet / WATER
  else:
  MenuChoice == "S"
  seconds = feet / STEEL
  
  #display ETA of the sound
  
  print "
  It will take", seconds, "second(s) for the sound wave to travel."
  [/code]
  
  again thank you so much for helping, I'll need more help between now (may 1st, 10:10pm est) and tomorrow 5pm with three other programs I have to build... I hope you can help some more.