Recursion - Java Concepts - page 847

Hint: This is a bit trickier than the preceding problem, because you must
keep track of how far the match is from the beginning of the sentence.
Make that value a parameter of a helper method.

΢ Exercise P13.6. Using recursion, find the largest element in an array.

public class DataSet
{
public DataSet(int[] values, int first, int
last) { È }
public int getMaximum() { È }
È
}

Hint: Find the largest element in the subset containing all but the last
element. Then compare that maximum to the value of the last element.

΢ Exercise P13.7. Using recursion, compute the sum of all values in an array.

public class DataSet
{
public DataSet(int[] values, int first, int
last) { È }
public int getSum() { È }
È
}

619
620

΢΢ Exercise P13.8. Using recursion, compute the area of a polygon. Cut off a
triangle and use the fact that a triangle with corners (x 1 , y 1 ), (x 2 , y 2 ), (x 3 ,
y 3 ) has area

| x 1 y 2

y 3 x 1 | + x 2 y 3 + x 3 y 1 ɨ y 1 x 2 ɨ y 2 x 3 ɨ

2