## CS 1401, Quiz 6

**Date:** Monday, October 16, 2006

**Name** (please type legibly, ideally in block letters):
______________________________________________________________________
1. Mark what is covered and what is not covered in Chapter 8:

- user-defined classes
*covered*
- private
*covered*
- arrays
*not covered*
- constructor methods
*covered*
- inheritance
*not covered*

2-4.

2. Write a method named *ex24* for computing the cubic root of
the sum of two given real numbers x and y. *Hint:* a cubic root
of a number z is equal to the number z raised to the power 1/3.

3. Call your method *ex24* in the *main* method to compute the cubic root
of a + b, where a = 3.0 and b = 5.0. (You do not need to write the entire
*main* method, just the part that assigns values to a and b and calls your
method.)

4. Trace, step by step, how the computer will perform the needed
computations, and check that the result is indeed correct.

Solution:
public double ex24(double x, double y){
double z = x + y;
return Math.pow(z,1.0/3.0);}
in the method main:
double a = 3.0;
double b = 5.0;
double c = ex24(a,b);
Tracing:
first,
--------- ---------
| 3.0 | | 5.0 |
--------- ---------
a b
------------------------
| -------- --------- |
| | 3.0 | | 5.0 ||
| -------- --------- |
| x y |
|------------------------|
| ---------- |
| | 8.0 | |
| ---------- |
| z |
------------------------
ex24
---------
| 2.0 |
---------
c