Functions, Control Structures and Expressions

1
Functions, Control Structures and Expressions

• Programming with Alice

2
Instruction
A statement that executes to make objects perform
a certain action.
3
Control Structure
A statement that controls the execution of a
block of instructions.
4
Function
Asks a question about a condition or computes a
value.
5
Expression
A mathematical operation on numbers or other
kinds of values.
6
Alice Control Structures

• Do In Order - done
• Do Together - done
• If/Else
• Repetition

7
If/Else

• Conditional execution uses functions and
  expressions to check a current condition in the
  world
• Is the spider robots head red?
• If the distance between the spider robot and rock
  greater than 1 meter?

8
If/Else

• You can use a function to ask questions about
  these an objects properties
• You can also use expressions to perform
  arithmetic operations on the values of those
  properties

9
Built-in Functions

• Proximity where is it in relation to other
  objects?
• Size how one objects size compares to another
  objects size
• Spatial Relation orientation (left or right) of
  one object to another
• Point of View position in the world
• Other

10
Possible Values in Alice

• Number
• Boolean (true or false)
• String (Hello)
• Object

11
Repetition (Loops)

• To add a loop, simply drag the loop statement
  into your program. It will prompt you to enter
  how many times you want the block of code to loop.

12
Fun Special Effects - Fog

• To add fog, click on World
• Now select properties
• Play around with the values until you get the
  effect you like