Conditionals

1. Try to evaluate the following numerical expressions in your head, then use Processing to check your results:
   1. 5 % 2
   2. 9 % 5
   3. 15 % 12
   4. 12 % 15
   5. 6 % 6
   6. 0 % 7
   7. 7 % 0

2. p and q are boolean variables. Evaluate each of the following expressions for all four combinations of values for p and q.
   1. !(p || q)
   2. p && q
   3. !(p && q)
   4. !p or !q
   5. !p and !q

3. The following Processing program draws a simple house.\\

  size( 320, 240 );
  rect( 20, 120, 100, 100 );    // the house
  rect( 55, 170, 30, 50 );      //  the door
  rect( 40, 140, 20, 20 );      // the left window
  rect( 80, 140, 20, 20 );      // the right window
  line( 20, 120, 70, 60 );      // the left roof
  line( 70, 60, 120, 120 );     // the right roof

Variables, Expressions and Statements

1. Take the sentence: All work and no play makes Jack a dull boy. Store each word in a separate variable, then print out the sentence on one line using println.
2. Add parenthesis to the expression 6 * 1 - 2 to change its value from 4 to -6.
3. In Processing, write a program that create a variable named bruce. The program should print the value the expression bruce + 4. Alter your program so that the value printed is 10.
4. What is the value of the following Processing expression?
   5 % 2
5. What is the result of evaluating the following expression?
   (1 + 2 * 2) / 2 + 1
6. How would you write the following formula as a Processing expression that produces a floating-point value as a result?
   {$ 9/5c + 32 $}
7. Which of the following are syntactically correct Processing statements? (assume all variables are int)
   • x * y = c;
   • y = con;
   • int x;
   • a = b % c;
8. f '''

Adapted from

• Elkner, Downey, and Meyers, How to Think Like a Computer Scientist.
• Dale, Weens and Headington, Programming and Problem solving with Java, Jones and Bartlett, 2003.

Processing Exercises

Adapted from J Elkner, AB Downey, and C Meyers, How to Think Like a Computer Scientist.