CS 1713 Introduction to Computer Science:
How to Draw Diagrams

• On the left side of the diagram, list all of the variables.
• Each variable is represented by a box labeled by its name.
• A variable box contains the current value of the variable.
• For variables of primitive type (int, double, char, boolean, etc):
  • The value of the variable is put in the box.
  • If the value of the variable changes, put a single line through the old value and insert the new value in the box.
  • Make your boxes large enough to show all of the past values of the variable.
• For variables which represent objects (including arrays):
  • The box will contain a reference to the object.
  • A reference is represented by an arrow with tail in the box and head pointing to the object value.
  • If the value of the variable changes, put a few lines through the old arrow and insert the new arrow whose tail is in the box and whose head points to the object.
• Objects are listed on the right side.
• Each object is represented by a box containing its state.
• The state is represented as a list of variables, each with a name and a box to hold its value.
• These variables are represented as before with a name and a box.
• For array objects, there is one variable for each element of the array.
• Use the index of the array element in place of the variable name, since array elements do not have names.