The following code can draw an O:

    yertle.up( )
    yertle.goto(-50, -70)
    yertle.down( )
    yertle.circle(20)

You should use the following template for your program:

#Program: drawXorO.py
#Include your program prologue here
from turtle import Pen as Turtle

yertle = Turtle( )

def drawX( ):
	#Write your code to draw an X here


def drawO( ):
	#Write your code to draw an O here
	
#Start the main program here
#Ask the user if they would like to draw an X or an O
#If they type X, call the drawX( ) function.
#If they type O, call the drawO( ) function.

The following is a sample output of the program:
Sample output 1:

Do you want to draw and X or an O? X

Problem 2: Once you have saved and printed out your program for problem 1, save it under a new name, drawXorOposition.py. Modify the two functions so that they now each take two parameters, a row number and a column number. The functions should now draw the X or the O at the position given by the row and column numbers (imagine 3 rows and 3 columns as in a tic-tac-toe game). You can have the turtle draw the X or O in a different place by changing the goto( ) command in each function.

For the drawX(row,col) function, change the goto( ) line to read:

yertle.goto(-70+col*50, -30+row*50)

For the drawO(row, col) function, change the goto( ) line to read:

yertle.goto(-50 + col*50, -70 + row*50)

Thus, as you increase the row number by 1, the position of the drawn X or O will shift up by 50 pixels. As you increase the column number by 1, the position of the drawn X or O will shift right by 50 pixels.

Now modify your main program to ask the user whether they want to draw an X or an O and what row and column they would like to draw it in. The program should then call the appropriate function, based on the user's answer, to draw the X or O in the appropriate place.

You may use the following program template:

#Program: drawXorOposition.py
#Include your program prologue here

from turtle import Pen as Turtle

yertle = Turtle( )

def drawX(row, col):
	#Write your code to draw an X here


def drawO(row, col):
	#Write your code to draw an O here
	
#Start the main program here
#Ask the user if they would like to draw an X or an O
#Ask the user to enter the row number
#Ask the user to enter the column number
#If they type X, call the drawX( ) function 
#	to draw an X in the correct row and column position.
#If they type O, call the drawO( ) function 
#	to draw an O in the correct row and column position.

The following are sample outputs of the program:
Sample output 1:

Do you want to draw and X or an O? O
Enter the row number: 0
Enter the column number: 2

Sample output 2:

Do you want to draw and X or an O? X
Enter the row number: 2
Enter the column number: 1

Problem 3.
Write a program named gradeAvg.py, to compute the average grade for a set of test scores. The program should prompt the user for the number of test scores to enter and read in that number. It should then call a function, GradeAverage(number), which will read in that number of test scores, compute their average and return that average. The main program has been written for you, you only need to write the GradeAverage(number) function.

The GradeAverage(number) function will use a for loop to do the following:

• Prompt for and enter a test score each time through the loop
• As each score is entered, that score should be added to a running sum of the scores.
• The number of times the loop is executed should be equal to the number of scores to be entered (given by the parameter).

After all the scores are entered, and their sum is complete, (i.e. after the for loop is finished), the function should return the average of the scores (the sum divided by the number of scores).

The GradeAverage() function should have one integer parameter (the number of scores to be read in and averaged) and should return a floating point numeric value (the average).

It should have 3 local variables: an integer variable to serve as a counter for the for loop, a real variable to read in each score, and a second real variable to keep track of the sum of scores.

Note: If all the scores entered are integers, you will need to cast the sum to a floating point number before computing the average (or Python will use integer division and truncate the decimal). To cast a variable to floating point, use the float( ) function. E.g. if the variable is named sum, the cast would be:

float(sum)

You should use the program skeleton given below. Do not change the main program. You only need to write the function, GradeAverage( ):

#Program: gradeAvg.py
#your name and program description goes here. 

#your definition for GradeAverage function goes here

numScores = input("How many scores do you want to enter? ")
average = GradeAverage(numScores)
print "The average score is %6.2f"%average

A sample session for the problem might look like the following:

How many scores do you want to enter? 3
Enter test score: 90
Enter test score: 91
Enter test score: 91
The average score is  90.67

What To Turn In.

Reminder.

Be sure to save a copy of each program on your P:\ drive.