Parameters, Local Variables, and Overloading
This chapter reviews method parameters and local variables, as well as method overloading and method signature.
Method overloading means two or more methods have the same name but have different parameter lists: either a different number of parameters or different types of parameters. When a method is called, the corresponding method is invoked by matching the arguments in the call to the parameter lists of the methods. The name together with the number and types of a method's parameter list is called the signature of a method. The return type itself is not part of the signature of a method.
13. Mystery of the Many Scopes
Answer:
int sum = 0;
for ( int j = 0; j < 8; j++ )
sum = sum + j;
System.out.println( "The sum is: " + sum );
Yes. Here the println() statement is within the scope of sum.
Mystery of the Many Scopes
Examine the following program. What does it print?
class Mystery
{
private int sum;
public Mystery( int sum )
{
this.sum = sum;
}
public void increment( int inc )
{
sum = sum + inc;
System.out.println("Mystery sum: " + sum );
}
}
public class Tester
{
public static void main ( String[] args)
{
int sum = 99;
Mystery myst = new Mystery( 34 );
myst.increment( 6 );
System.out.println("sum: " + sum );
}
}
Notice that the identifier sum is used for three different things:
- The instance variable of a
Mysteryobject. - The parameter of the
Mysteryconstructor. - The local variable of the
main()method.
Question 13:
What is printed?