Solution to problem 1.

#Program: drawXorO1.py
#Author: Brenda Student
#Class: CSCI 110
#Date: 3/11/11
#Assignment: Lab 5
#Purpose: Draw an X or an O depending on the user's request

from turtle import Pen as Turtle

yertle = Turtle( )

def drawX():
    yertle.up( )
    yertle.goto(-70, -30)
    yertle.down( )
    yertle.right(45)
    yertle.forward(57)
    yertle.up( )
    yertle.left(45)
    yertle.backward(40)
    yertle.left(45)
    yertle.down( )
    yertle.forward(57)
    yertle.right(45)


def drawO(row, col):
    yertle.up( )
    yertle.goto(-50, -70)
    yertle.down( )
    yertle.circle(20)


answer = raw_input("Do you want to draw and X or an O? ")
if answer == "X":
    drawX( )
else:
    drawO( )

Solution to problem 2.

#Program: drawXorOposition.py
#Author: Brenda Student
#Class: CSCI 110
#Date: 3/11/11
#Assignment: Lab 5
#Purpose: Draw an X or an O at a position specified by the user.

from turtle import Pen as Turtle

yertle = Turtle( )

def drawX(row, col):
    yertle.up( )
    yertle.goto(-70+col*50, -30+row*50)
    yertle.down( )
    yertle.right(45)
    yertle.forward(57)
    yertle.up( )
    yertle.left(45)
    yertle.backward(40)
    yertle.left(45)
    yertle.down( )
    yertle.forward(57)
    yertle.right(45)


def drawO(row, col):
    yertle.up( )
    yertle.goto(-50 + col*50, -70 + row*50)
    yertle.down( )
    yertle.circle(20)


answer = raw_input("Do you want to draw and X or an O? ")
rowNum = input("Enter the row number: ")
colNum = input("Enter the column number: ")
if answer == "X":
    drawX(rowNum, colNum )
else:
    drawO(rowNum, colNum )

Solution to Problem 3:

#Program: gradeAvg.py
#Author: Brenda Student
#Class: CSCI 110
#Date: 3/11/11
#Purpose: Computes grade average from test scores}

#definition for GradeAverage function
def GradeAverage(number):
    sum = 0
    for x in range(number):
        newScore = input("Enter test score: ")
        sum = sum + newScore
    average = float(sum)/number
    return average

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