Understanding Looping in NetLogo Programming

1. New Mexico Computer Science For All More Looping in NetLogo Maureen Psaila-Dombrowski

2. Types of Loops • Already know that there are three common types of loops in most programming languages: • Infinite Loops • Counted Loops • Conditional Loops

3. Components of a Loop • Loops have some properties in common: • Body of the loop: The portion of the code that is repeated. • Iteration:Number of times the loop is executed • Some types of loops have other properties • Loop Variable: A variable that is incremented during the looping process • Loop Condition: A conditional (true of false) statement that is checked during looping

4. Infinite Loops • An infinite loop repeats the body of the loop until one of the following occurs: • A“stop” command in the program • Manually turned off. • A runtime error. • Already familiar with this in NetLogo

5. Counted Loops • Repeated a fixed maximum number of times. • Must know how many times • Before programming • Be able to calculate maximum number of times

6. Counted Loops in Netlogo • Netlogo has a specific command for counted loops, the REPEAT command repeat Nnumber [ commands ] • The commands in the square brackets [] are repeated Nnumber of times.

7. Example of Counted Loops Netlogo

8. Conditional Loops • Repeated while a certain conditional statement is true. • Must establish the condition statement initially and it must be true for the loop to start • The condition must become false during the looping process in order for the loop to stop, otherwise the loop becomes infinite.

9. Conditional Loops in Netlogo • Netlogo has a specific command for conditional loops, the WHILE command while [condition] [ commands ] • The commands in the square brackets [] are repeated while the condition is true. • When the condition becomes false, the loop is exited.

10. Example of Conditional Loop in Netlogo

11. Summary • Three types of loops • Infinite Loops • Counted Loops- the REPEAT command repeat Nnumber [ commands ] • Conditional Loops - the WHILE command while [condition] [ commands ]