name error global name 'x' is not defined...help

[Johnny James]

import subprocess
import sys
import time
import os
 
def main():
    #Check to see if quickdraw is located in the correct palce
    quickfile = file_existance()
    quickdraw = subprocess.Popen(['java', '-jar', quickfile], stdin = subprocess.PIPE)
    #Intro, explaining what will occur throughout program
    intro()
    #
    x_coordinate(1)
    y_coordinate(1)
    initial_ball(quickdraw)
 
 
def file_existance():
        filename = raw_input("Please enter the name of the file: ")
        while (not os.path.isfile(filename)):
                print "That file does not exist, try again"
                filename = raw_input("Please enter the name of the file: ")
        print os.path.abspath(filename)
        return filename
 
def intro():
    print "For this assignment you will be asked to give coordinates for a ball,"
    print "after you have given the coordinates, the ball will continually bounce"
    print "until it runs out of energy and comes to a complete stop."
 
def x_coordinate(num):
    num= num+1
    x= int(input("Please enter the x-coordinate (between 0 and 600) where you would like the ball placed: "))
    if (x <= 600) and (x >= 0):
        print "Valid choice"
        return x
    else:
        print "invalid choice, choose again please"
        if num > 3:
            x = 300
            return x
        else:
            x_coordinate(num)
    return x
 
def y_coordinate(num):
    num= num+1
    y= int(input("Please enter the y-coordinate (between 0 and 600) where you would like the ball placed: "))
    if (y >= 0) and (y <= 600):
        print "Valid choice"
        return y
    else:
        print "invalid choice, choose again please"
        if num > 3:
            y = 300
            return y
        else:
            y_coordinate(num)    
 
 
 
def initial_ball(quickdraw):
    radius= 300
    ball = "fillcircle" + ' ' + str(x) + ' ' + str(y) + ' ' + str(radius)
    quickdraw.stdin.write(ball)
    quickdraw.stdin.write("\n") 
 

The error is that the global name 'x' is not defined. But I dont understand why because I returned the variable...

[bvdet]

You should assign x_coordinate(1) to an identifier and pass that as an additional parameter to initial_ball(). You must do the same for y_coordinate(1).

You could also do this:

    initial_ball(quickdraw,
                 x_coordinate(1),
                 y_coordinate(1))

Redefine initial_ball: def initial_ball(quickdraw, x, y):