STAT 243 ASSIGNMENT 1 FALL, 2009
due October 5, 2009
1. Function Prototypes
Consider the following function, which adds two double precision floating point numbers:
double sum(double x, double y)
{
return(x + y);
}
For this assignment, create a file containing this function definition, and a second file with
a program which calls the sum function using two integer arguments, and which prints the
value returned by sum. Compile and run the program twice, first declaring sum as
double sum();
and then using a function prototype, like
double sum(double,double);
Does the value printed by the program when you use the first declaration agree with the value
when you use the function prototype? Explain why or why not.
2. Determining Machine Constants
Write a program (or programs) to determine the following:
•Largest Integer What is the largest integer (both long and short) that can be handled
in the computer? What happens when an integer becomes larger than this due to a
computation?
•Largest Unsigned Integer What is the largest unsigned integer (both long and short)
that can be handled in the computer? What happens when an unsigned integer becomes
larger than this due to a computation?
•Largest Floating Point Number What is the largest floating point number (both
single and double precision) which can be handled in the computer? What happens
when a number becomes larger than this due to a computation?
•Machine Epsilon One important constant on the computer is the smallest number
such that, when it is added to 1, the result is greater than 1. What is the value of
machine epsilon?
The simplest way to determine these constants is to write a program which starts with the
number 1, and then multiplies or divides it by 2, printing out the result at each stage. These
results can be examined, and it is usually pretty clear what the value of the constant is. A
better solution is to write a program which can detect when the constant has been found, and
to break out of the loop and print the answer at that time. The first solution is acceptable,
but try to aim for the second method.
Note: Most of the values described above can be found in a header file in the standard include
directory /usr/include. If you can find the appropriate header file, it may be of interest to
compare the results in that file with the results of your program. (Please note that finding
the header file does not constitute completing the assignment.)
