Exercises

Pythagorean Triples
Execution speed test

Pythagorean Triples

A right triangle can have sides that are all integers. A set of three integer values for the sides of a right triangle is called a Pythagorean triple. These three sides must satisfy the relationship that the sum of the squares of two of the sides is equal to the square of the hypotenuse. I.e. side a squared plus side b squared equals the hypotenuse squared in a right triangle. So a² + b² = c²

This is a program that finds all Pythagorean triples for side1, side2, and the hypotenuse. The program uses a triple-nested for loop that tries all possibilities. This is an example of "brute force" computing.

The answers are displayed in a list box. In any graphical system, screen updates are CPU intensive. To get a more accurate accounting of true execution speed, entering a negative number will suppress the output.

Also the elapsed time for the program to compute the solution is displayed.

Java primitive data types to represent numbers.

Integers

Type	Size	Minimum value	Maximum value
byte	8 bits	-128	127
short	16 bits	-32768	32768
int	32 bits	-2147483648	2147483647
long	64 bits	-9223372036854775808	9223372036854775807

Floating point

Type	Size	Largest value	Smallest value	Precision
float	32 bits	±3.4E+38	±1.4E-45	6 - 7 significant figures
double	64 bits	±1.79E+308	±4.94E-324	14 - 15 significant figures

The problem exercise has been written using each of the primitive data types. The exercise was run on an IBM R40 laptop that contains a 32 bit Intel mobile P4 CPU.

Byte, with its small max value really doesn't provide much insight regarding execution speed.
Short, int, and float data types all take about the same amount of time to execute.
Double takes about 75% longer to execute.
Long takes the most time (100% or twice the time) to execute. Interestingly, more time than the double.

If this exercise was run on a 64 bit processor, such as the Intel Itanium 64 bit processor or the AMD Opteron, would all data types take about the same length of time to execute? If anyone know the answer to this question, email me at abenusa@ridgewater.mnscu.edu.

Byte data type.