CS21: Quiz 2 Study Guide

In addition to all concepts from Quiz 1

You should be able to define the following terms:

You should understand and be able to use the following Python concepts:

Practice problems:

  1. Show the output from the following code fragments:
for i in range(4):
      print(i)
      print("--")
for x in range(6):
      print(x, x**2)
print("done!")
text = "hello!"
for i in range(len(text)):
      print("-" + text[i] + "-")
  1. Write a program that asks the user for their name, and then prints their name 20 times.

  2. Given these assignments:

x = 5
y = 13
S = "we love computer science"

Show the value and type of each expression below:

x < 10 and y < 10
x < 10 or y < 10
x < 10 and x > 0
x > 10 or x < 0
(5/x) > 7.0
len(S) >= 10
S[0] < S[1]
  1. Trace the following program and show it’s output:
x = 3
print("%d  %d" % (0,x))
for i in range(5):
    if x % 2 == 0:
        x = x / 2
    else:
        x = (3*x+1)/2
    print("%d  %d" % (i,x))
  1. Write a program that asks the user how many grades they want to average, reads in those grades and prints their average.
Enter number of grades to average: 5

Enter grade: 96
Enter grade: 86
Enter grade: 76
Enter grade: 66
Enter grade: 56

Average is: 76.0