CPSC 120 Postlab 2: Finding Your Pace Due Monday September 18, 2006 at class time

Overview

For runners, race distances are often given in kilometers -- 5K, 10K, etc. A fast runner might run a 5K race in 20 minutes or so; the winning time is usually closer to 15 minutes, and most of the population comes in between 20 and 35 minutes. It's interesting to think of what these times translate to in miles per hour (MPH). In this assignment you will write a program that relates the user's race time to their speed in MPH.

• The distance of the race, in kilometers
• The minutes part of their finish time
• The seconds part of their finish time

Your program should print the user's pace in MPH, then ask the user what pace he or she is trying to achieve. After reading in this information, the program should print what time the user would need to run a race of the given distance in to achieve this pace.

A sample run of your program for a user who ran a 5K in 27 minutes and 15 seconds might look like this (items in bold are entered by the user):

Enter the number of kilometers run: 5
Enter the minutes part of your time: 27
Enter the seconds part of your time: 15
How fast do you want to go, in MPH? 10
To go that fast, you would have to run your distance in 18.75 minutes.

• First declare your variables and constants. You will probably need variables to hold the distance in kilometers, the distance in miles, the minutes part of the time, the seconds part of the time, the total seconds, the time in hours, the pace in MPH, the desired pace, and the time required for the desired pace. Phew! Think about what type each of these should be. Note that there are 1.6 kilometers in a mile and 3600 seconds in an hour (these should be constants!!).

• Next, do the calculations to get the distance in miles and the time in hours. It's easy to convert the distance to miles -- just use the conversion factor above. But be sure to use it the right way! Note that 5 kilometers is about 3.1 miles; this should help you see if your answers make sense.

• Converting the time to hours will take a little more thought. First convert the minutes part to seconds, then add the result to the seconds part entered by the user. This gives you the total time in seconds, which you can convert to hours using the conversion factor above.

• Once you have the distance in miles and the time in hours, it's simple to get the pace in MPH -- just divide.

• When the user enters their desired pace, it's also easy to calculate the necessary time in hours; just solve the formula (pace = miles/hours) for hours, since you know both the pace and the miles. Of course, you'll need to convert the result to minutes to print it out.
Be sure to put your name, the file name, and a description of the program in the header.

What to turn in

Turn in hardcopy of your program and e-mail the .java file to your instructor @roanoke.edu with cpsc120 post2 in the subject.