CS21 Lab1: First Programs
This lab assignment requires you to write three programs in Python. First, run update21. This will create the cs21/labs/01 directory (if you haven't already) and copy over any starting-point files for your programs. Next, move into your cs21/labs/01 directory and begin working on the Python programs for this lab. The pwd command helps you verify that you are in the correct sub-directory.
$ update21 $ cd cs21/labs/01 $ pwd /home/your_user_name/cs21/labs/01We will only grade files submitted by handin21 in this directory, so make sure your programs are in this directory!
As you write your first programs, start using good programming practices now:
- Use a comment at the top of the file to describe the purpose of the program.
- Use variable names that describe the contents of the variables.
- Use def main() to combine the steps of your program into a function.
- Write your programs incrementally and test them as you go. This is really crucial to success: test, test again, and then test some more! Don't assume that if your program passes the sample tests we provide that it is completely correct. Come up with your own test cases and verify that the program is producing the right output on them.
Each Dove dark chocolate has 42 calories. Write a program that asks the user how many Dove dark chocolates they ate, then calculates and displays how many calories that is. You may assume the user will enter valid integers. Here are some sample runs showing how your program should work:
$ python dove.py How many Dove dark chocolates did you eat? 1 That's 42 calories! $ python dove.py How many Dove dark chocolates did you eat? 5 That's 210 calories! $ python dove.py How many Dove dark chocolates did you eat? 200 That's 8400 calories!
Write a program that asks the user to enter a race pace in minutes and seconds (how long it takes to run one mile), and then calculates the race time for a 5K race. Here's how the program should work:
$ python fivek.py Give me your mile pace (minutes & seconds per mile) and I'll calculate your 5K race time. minutes: 8 seconds: 30 5K race time at that pace: 26:21
For the above example, the user intends to run the race at a pace of 8 minutes, 30 seconds per mile, so a 5K (3.1 miles) will take 26 minutes and 21 seconds to finish.
Hint: for this one, it is probably easiest to follow this algorithm:
- convert the race pace into seconds (e.g., 8:30 is 510 seconds)
- figure out the race time in seconds (i.e., how many seconds to run 3.1 miles)
- convert the race time in seconds back to minutes:seconds
Here are some additional examples to test your program:
$ python fivek.py Give me your mile pace (minutes & seconds per mile) and I'll calculate your 5K race time. minutes: 6 seconds: 12 5K race time at that pace: 19:13 $ python fivek.py Give me your mile pace (minutes & seconds per mile) and I'll calculate your 5K race time. minutes: 10 seconds: 0 5K race time at that pace: 31:0
Let's see how much exercise you need to do to burn off all of the calories from those Dove chocolates you ate!
This Calories Burned By Heart Rate Calculator uses the following formulas:
Men: CaloriesBurned = ((AGE * 0.2017) + (WEIGHT * 0.1988)+ (HR * 0.6309) - 55.0969) * DUR / 4.184 Women: CaloriesBurned = ((AGE * 0.074) - (WEIGHT * 0.1263) + (HR * 0.4472) - 20.4022) * DUR / 4.184
where the AGE is in years, the WEIGHT is in kg, HR is the heart rate in beats-per-minute, and DUR is the exercise duration in minutes.
Write a program that asks the user for AGE, WEIGHT, exercise DURATION, and a starting HEARTRATE, and then displays a table of values, using the above formulas, for various HEARTRATEs. Your table should start with the given HEARTRATE, but include 10 more, evenly spaced by 10s.
Below are some sample runs showing how your program should work.
$ python cals.py
Calories Burned vs Heart Rate Calculator
Age in years: 49
Weight in kg: 72.5
Exercise Duration in minutes: 30
Minimum Heart Rate in bpm: 70
HR CB (Men) CB (Women)
---- --------------------
70 95.8 38.5
80 141.0 70.6
90 186.3 102.6
100 231.5 134.7
110 276.8 166.8
120 322.0 198.8
130 367.2 230.9
140 412.5 263.0
150 457.7 295.0
160 502.9 327.1
170 548.2 359.2
$ python cals.py
Calories Burned vs Heart Rate Calculator
Age in years: 20
Weight in kg: 54.4
Exercise Duration in minutes: 60
Minimum Heart Rate in bpm: 85
HR CB (Men) CB (Women)
---- --------------------
85 191.8 175.2
95 282.3 239.4
105 372.8 303.5
115 463.3 367.6
125 553.7 431.7
135 644.2 495.9
145 734.7 560.0
155 825.2 624.1
165 915.6 688.3
175 1006.1 752.4
185 1096.6 816.5
Remember you may run handin21 as many times as you like. Each time you run it new versions of your files will be submitted. Running handin21 after you finish a program, after any major changes are made, and at the end of the day (before you log out) is a good habit to get into.