1. Control structures
Chapter 3

2. Topics Assignment statement Selection: if..else
Multi-way selection: switch
Repetition
Functions: setup(), draw(), mousePressed()

3. Repetition
Three kinds of loops
For loop
While loop
Do while loop

4. Loops syntax While loop int i =0; while (i < 100) { do something;
i = i + 1; }
For loop
for (int i =0; i < 100; i = i +1) {

5. Loops syntax (contd.)
int i = 0; do { do something; i = i + 1; } while (i < 100);

6. Lets apply this to drawing some shapes
On to Processing:
Draw 10 rectangles of different sizes and at different locations
Draw 10 circles of different sizes and at different locations
Parameter passing

7. Local Variables and Scope
void setup() { int locVar1 = 301; println(“ lacvar1 in setup = “, locVar1); { int locVar2 = 290; println(“ locVar1 nested in setup = +“ locVar1); println(“locVar2 nexted in setup = +”locVar2); } println(“ local locVar2 out of scope = “+ locVar2); void func() println(“ local locVar1 out of scope = “+ locVar1);
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8. Boolean variable
What are the different types of variable you have learned so far? int, float, char
Here is one more: boolean
A boolean varaible can take “true” or “false” as values.
How to define it?
How to initialize it?
How to use it?
boolean win;
win = true;
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9. Variable naming conventions
Variable name begin with lower case and the first word is all lowercase.
If there are more than one word in the variable you begin the second with an upper case; do that same for more than two words of variable names too.
Examples:
setup
draw
drawAnimal
drawAfricanAnimal
drawSquaresCircles
mySalary
myDocs
myNameAddressGrade
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10. Selection statement We already studied if..else
See some examples in your text
Lets look at out lab 1 and see how we use this if..else
if (condition)
{ statements to be executed }
else
{ statements to be executed}
We could use nested if..else for multi-way selection..
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11. Switch statement: multi-way selection
Format or syntax:
switch(val) {
case 0: do this; break;
case 1: do this; break;
default: do this; }
// lets use this in an example
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12. Example for switch
int ct=0; int count = 0; int counta=0; int countb=0; int countc=0; void keyPressed() { switch (key) case 'a' : ct = counta++; break; case 'b' : ct = countb++; break; case 'c' : ct = countc++; break; default: ct = count++; } println(ct);