Programming Forums > Script Programming > Python

Sane · Oct 30th, 2007, 10:36 PM

Quote:

And print out the output in a way the user can understand.

Your code needs print statements if you want to see output. Print out all four variables, root1r, root1i, root2r, root2i, in a format you want your user to see.

A useful thing would be to use "format specifiers". I don't want to confuse you, but this code might help, if you feel ambitious enough to understand it:

Essentially, each %s is replaced with the next variable enclosed inside the brackets.

(Toggle Plain Text)

name = "Aaron"
language = "Python"
word = "fun"

print "Hello, my name is: %s. I program in %s and have a lot of %s with it."%( name, language, word )

acwbrat · Oct 30th, 2007, 10:42 PM

What am I doing wrong?

(Toggle Plain Text)

import math

def main(): # beginning of the code
    print "Hello! This program finds the real and complex solutions to a quadratic"
    print

    a, b, c = input("Please enter the coefficients (a, b, c): ")

    disc = (b*b-4*a*c) # discriminant
    if disc < 0:
        disc = -disc    # force it to be positive
    else:
        print "This quadratic does not have imaginary roots"
        return

    discRoot = math.sqrt(b*b-4*a*c)

    root1r = (-b) / (2 * a)      # the real portion of root1
    root1i = discRoot / (2 * a)  # the imaginary portion of root1
    
    root2r = root1r      # the real portions are the same for each root
    root2i = -root1i     # the only difference is it's negative

main()

Sane · Oct 30th, 2007, 10:44 PM

You used to have

(Toggle Plain Text)

discRoot = math.sqrt(disc)

But for some reason you've now got it as

(Toggle Plain Text)

discRoot = math.sqrt(b*b-4*a*c)

Put it back.

Also, you're still not printing your output at the end.

acwbrat · Oct 30th, 2007, 10:45 PM

When inputting a=1 b=-10 c=34

The code doesn't display the results but rather goes back to the prompt.

acwbrat · Oct 30th, 2007, 10:49 PM

Here is what I have right now:

(Toggle Plain Text)

import math

def main(): # beginning of the code
    print "Hello! This program finds the real and complex solutions to a quadratic"
    print

    a, b, c = input("Please enter the coefficients (a, b, c): ")

    disc = (b*b-4*a*c) # discriminant
    if disc < 0:
        disc = -disc    # force it to be positive
    else:
        print "This quadratic does not have imaginary roots"
        return

    discRoot = math.sqrt(disc)

    root1r = (-b) / (2 * a)      # the real portion of root1
    root1i = discRoot / (2 * a)  # the imaginary portion of root1
    
    root2r = root1r      # the real portions are the same for each root
    root2i = -root1i     # the only difference is it's negative

    print %s %s %s %s root1r, rooti, root2r, rooti
    print

main()

Sane · Oct 30th, 2007, 10:49 PM

Your print syntax doesn't match my example. You need quotations. You need the % sign. And you need () around your variables. Syntax in programming can be understandably picky. If you follow my previous example.

(Toggle Plain Text)

    print "%s %s %s %s"%(root1r, rooti, root2r, rooti)
    print

But you got some of your variable names wrong. rooti should be root1i, same with root2i.

Then you can format it more nicely like so:

(Toggle Plain Text)

    print "%s+%si , %s+%si"%(root1r, root1i, root2r, root2i)
    print

acwbrat · Oct 30th, 2007, 10:57 PM

I'm sorry but what happened to the imaginary numbers or the complex numbers for the quadratic formula? I had to refresh myself on calculating the quadratic formula and I don't know if this code it computing the imaginary numbers/complex numbers. Maybe I am just confused.

Sane · Oct 30th, 2007, 11:00 PM

This code is outputting the real and imaginary parts of the complex roots.

For example. y = 1x^2 + 2x + 2 has the roots "-1+1i and -1-1i". Running the program with 1, 2, 2 verifies that.

Let me guess, all along you wanted the complex roots in polar form? =/

acwbrat · Oct 30th, 2007, 11:02 PM

OMG!! IT WORKED!!! The code worked!!! Yaaaaaaaaaaaaaaaaaaaaaay!!!! Thank you Sane!!!

acwbrat · Oct 30th, 2007, 11:04 PM

All along, I've been doing this code wrong by using import cmath and also just not knowing the tricks and trades in %s %i. That's wonderful!!! I feel a lot better now!

Oct 30th, 2007, 10:42 PM	#12
acwbrat Newbie Join Date: Oct 2007 Posts: 17 Rep Power: 0	Re: Quadratic Formula in Python What am I doing wrong? (Toggle Plain Text) import math def main(): # beginning of the code print "Hello! This program finds the real and complex solutions to a quadratic" print a, b, c = input("Please enter the coefficients (a, b, c): ") disc = (bb-4ac) # discriminant if disc < 0: disc = -disc # force it to be positive else: print "This quadratic does not have imaginary roots" return discRoot = math.sqrt(bb-4ac) root1r = (-b) / (2 * a) # the real portion of root1 root1i = discRoot / (2 * a) # the imaginary portion of root1 root2r = root1r # the real portions are the same for each root root2i = -root1i # the only difference is it's negative main() import math def main(): # beginning of the code print "Hello! This program finds the real and complex solutions to a quadratic" print a, b, c = input("Please enter the coefficients (a, b, c): ") disc = (bb-4ac) # discriminant if disc < 0: disc = -disc # force it to be positive else: print "This quadratic does not have imaginary roots" return discRoot = math.sqrt(bb-4ac) root1r = (-b) / (2 * a) # the real portion of root1 root1i = discRoot / (2 * a) # the imaginary portion of root1 root2r = root1r # the real portions are the same for each root root2i = -root1i # the only difference is it's negative main()

Oct 30th, 2007, 10:44 PM	#13
Sane Programming Guru Join Date: Apr 2005 Posts: 1,799 Rep Power: 5	Re: Quadratic Formula in Python You used to have (Toggle Plain Text) discRoot = math.sqrt(disc) discRoot = math.sqrt(disc) But for some reason you've now got it as (Toggle Plain Text) discRoot = math.sqrt(bb-4ac) discRoot = math.sqrt(bb-4ac) Put it back. Also, you're still not printing your output at the end.

Oct 30th, 2007, 10:45 PM	#14
acwbrat Newbie Join Date: Oct 2007 Posts: 17 Rep Power: 0	Re: Quadratic Formula in Python When inputting a=1 b=-10 c=34 The code doesn't display the results but rather goes back to the prompt.

Oct 30th, 2007, 10:49 PM	#15
acwbrat Newbie Join Date: Oct 2007 Posts: 17 Rep Power: 0	Re: Quadratic Formula in Python Here is what I have right now: (Toggle Plain Text) import math def main(): # beginning of the code print "Hello! This program finds the real and complex solutions to a quadratic" print a, b, c = input("Please enter the coefficients (a, b, c): ") disc = (bb-4ac) # discriminant if disc < 0: disc = -disc # force it to be positive else: print "This quadratic does not have imaginary roots" return discRoot = math.sqrt(disc) root1r = (-b) / (2 a) # the real portion of root1 root1i = discRoot / (2 * a) # the imaginary portion of root1 root2r = root1r # the real portions are the same for each root root2i = -root1i # the only difference is it's negative print %s %s %s %s root1r, rooti, root2r, rooti print main() import math def main(): # beginning of the code print "Hello! This program finds the real and complex solutions to a quadratic" print a, b, c = input("Please enter the coefficients (a, b, c): ") disc = (bb-4ac) # discriminant if disc < 0: disc = -disc # force it to be positive else: print "This quadratic does not have imaginary roots" return discRoot = math.sqrt(disc) root1r = (-b) / (2 a) # the real portion of root1 root1i = discRoot / (2 * a) # the imaginary portion of root1 root2r = root1r # the real portions are the same for each root root2i = -root1i # the only difference is it's negative print %s %s %s %s root1r, rooti, root2r, rooti print main()

Oct 30th, 2007, 10:49 PM	#16
Sane Programming Guru Join Date: Apr 2005 Posts: 1,799 Rep Power: 5	Re: Quadratic Formula in Python Your print syntax doesn't match my example. You need quotations. You need the % sign. And you need () around your variables. Syntax in programming can be understandably picky. If you follow my previous example. (Toggle Plain Text) print "%s %s %s %s"%(root1r, rooti, root2r, rooti) print print "%s %s %s %s"%(root1r, rooti, root2r, rooti) print But you got some of your variable names wrong. rooti should be root1i, same with root2i. Then you can format it more nicely like so: (Toggle Plain Text) print "%s+%si , %s+%si"%(root1r, root1i, root2r, root2i) print print "%s+%si , %s+%si"%(root1r, root1i, root2r, root2i) print

Oct 30th, 2007, 10:57 PM	#17
acwbrat Newbie Join Date: Oct 2007 Posts: 17 Rep Power: 0	Re: Quadratic Formula in Python I'm sorry but what happened to the imaginary numbers or the complex numbers for the quadratic formula? I had to refresh myself on calculating the quadratic formula and I don't know if this code it computing the imaginary numbers/complex numbers. Maybe I am just confused.

Oct 30th, 2007, 11:00 PM	#18
Sane Programming Guru Join Date: Apr 2005 Posts: 1,799 Rep Power: 5	Re: Quadratic Formula in Python This code is outputting the real and imaginary parts of the complex roots. For example. y = 1x^2 + 2x + 2 has the roots "-1+1i and -1-1i". Running the program with 1, 2, 2 verifies that. Let me guess, all along you wanted the complex roots in polar form? =/

Oct 30th, 2007, 11:02 PM	#19
acwbrat Newbie Join Date: Oct 2007 Posts: 17 Rep Power: 0	Re: Quadratic Formula in Python OMG!! IT WORKED!!! The code worked!!! Yaaaaaaaaaaaaaaaaaaaaaay!!!! Thank you Sane!!!

Oct 30th, 2007, 11:04 PM	#20
acwbrat Newbie Join Date: Oct 2007 Posts: 17 Rep Power: 0	Re: Quadratic Formula in Python All along, I've been doing this code wrong by using import cmath and also just not knowing the tricks and trades in %s %i. That's wonderful!!! I feel a lot better now!

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Programming Forums > Script Programming > Python

Quadratic Formula in Python