Java Programming Week 3

What is the anatomy of defining a method in Java?

void <name>() {

<statements> — ( method’s body )

}

How do you call a method?

<name>()

What are some aspects in terms of statement organization?

• Methods can group statements

• Hide local variables and implementation

• Hidden == not changeable/visible by the outside code

Why is hiding information good?

• Reduces dependencies in the program between parts of the program

• Decrease complexity

• Increase flexibility

What does “double” from double method (int parameter ) mean

It is the return type

What does “int parameter” from double method (int parameter ) mean

• It is the passed parameter that you can pass upon calling

• Parameter is hidden from outside code

What is difference between methods and functions?

Functions are methods with a return value

What does void mean

The function returns nothing

Where are other methods declared

They are declared at class level not inside other methods

What is the scope of parameters and variables of a method?

They are not visible from the outside code

What is the general idea of recursion?

Divide the problem into:

• Base cases where method returns x,1,false etc

• And Reduction to the same problem but of smaller size

What does mutual recursion mean?

The recursion is not a direct call but rather via other method.

f calls g and g calls f

Which is the situation where you use recursion?

When a recursive definition or recurrence relation is known

Which is faster recursion or iteration

Iteration

What are typical errors in recursion?

• no or incomplete base cases

• not always reduction in size

• too many steps in size reduction part