|ITP1170x||Project #1||Spring 2011|
In this project you are going to write a C++ program which will declare variables, read values into and write the values stored in those variables, and perform various calculations and assignments using them.
Imagine that you are developing a system to help a weather station process weather observations (temperature, wind, air pressure, and humidity). The purpose of the program is to help convert data from one set of units to another, to calculate the wind speed from the motion of a weather balloon, and to express humidity data in different forms. In order to be able to handle data collected in different formats, you must be able to convert from various units of measure to other units. Your program will prompt the user to enter values in certain units and then print out both the original values and the values in the other units.
You will be required to write a C++ program to do the conversions explained in this section. As you read this section, you may also want to refer to the ``Sample output'' section below.
Your program is to first print certain introductory information and read certain required input values from the user. It will then print 4 separate sections of output giving the calculated values.
Your program must first print a welcome message: Welcome to ``Weather Wizard'' Unit Converter! ``Weather Wizard'' must be printed in double quotes as shown above. The program must then request a set of temperature and air pressure values in English units (degrees Fahrenheit and inches of mercury). There must be a blank line between any two requests for values. This section should be preceded by the message: Please enter values in `ENGLISH' units: The word ``ENGLISH'' must be printed in single quotes as shown above. Following this message, the program must prompt the user on a separate line to enter a temperature in degrees Fahrenheit. This prompt must contain the exact words ``temperature'' and ``Fahrenheit''. The program must then read in a single temperature value. This number will be an integer. Following a blank line, the program must prompt the user to enter a pressure in inches. This prompt must contain the exact words ``pressure'' and ``inches''. The program must then read in a single pressure value. This number will be a positive value, possibly with a fractional part.
The program must then request a set of temperature and air pressure values in metric units (degrees Celsius and millibars). There must be a blank line between any two requests for values. This section should be preceded by the message: Please enter values in `METRIC' units: The word ``METRIC'' must be printed in single quotes as shown above. Following this message, the program must prompt the user on a separate line to enter a temperature in degrees Celsius. This prompt must contain the exact words ``temperature'' and ``Celsius''. The program must then read in a single temperature value. This number will be an integer. Following a blank line, the program must prompt the user to enter a pressure in millibars. This prompt must contain the exact words ``pressure'' and ``millibars''. The program must then read in a single pressure value. This number will be a positive value, possibly with a fractional part.
Following a blank line, the program must then print a header message for the wind calculator. This message must contain the exact words ``Wind'' and ``Calculator''. On the next line, the program is to print a prompt for the user to enter the number of miles and feet traveled by the weather balloon. The program must then read in a value for the miles and a value for the feet traveled. These numbers will be non-negative integers. On the next line, the program is to print a prompt for the user to enter the amount of time the balloon has been traveling, in minutes and seconds. The program must then read in a value for the minutes and a value for the seconds of time. These numbers will be non-negative integers.
Following a blank line, the program must then print a header message for the humidity calculator. This message must contain the exact words ``Humidity'' and ``Calculator''. On the next line, the program is to print a prompt for the user to enter the Fahrenheit air temperature and dew point temperature. The program must then read in 2 values representing the appropriate temperatures. These numbers will be integers.
Your program may assume, without checking, that the user will enter the proper number of values which will be of the types described above and whose values will always be within the ranges indicated.
After the input values are read, your program is to print 10 asterisks () preceded and followed by blank lines, followed by its first section of output. The first line of this output section must contain the phrase ``English to metric conversion''. The next line of output must contain the Fahrenheit temperature value read in, followed by the equivalent temperature in Celsius. Both temperature values must be printed on the same line, and each value must be labeled in the appropriate units. The temperature values should be printed rounded to the nearest whole degree. On the next line, the program must print the air pressure value read in, followed by the equivalent value in millibars. Both pressure values must be printed on the same line, and each value must be labeled in the appropriate units. The value in inches must be printed with an accuracy of 2 decimal places, and the value in millibars must be printed rounded to the nearest whole millibar.
After the first output section is printed, your program is to print a blank line followed by its second section of output. The first line of this output section must contain the phrase ``Metric to English conversion''. The output for this section will follow the same pattern as the first section above, except the metric units read in will be followed by their equivalent English units. The values must be printed with the same accuracy and the same labeling as described for the first output section above.
After the second output section is printed, your program is to print a blank line followed by its third section of output. The first line of this output section must contain the phrase ``Wind calculator results''. On the next line, the program must print the wind speed in feet per second, miles per hour, and knots. The three values are to be labeled ``feet/sec'', ``mph'', and ``kt'' respectively. The value in feet/sec must be printed with an accuracy of 2 decimal places, and the values for mph and kt are to be printed rounded to the nearest whole unit.
After the third output section is printed, your program is to print a blank line followed by its fourth section of output. The first line of this output section must contain the phrase ``Humidity calculator results''. On the next line, the program must print the air temperature, the dew point temperature, and the relative humidity in that order. The temperature values must be printed in units of whole degrees Fahrenheit, and the relative humidity must be printed rounded to the nearest whole percent. The temperatures must be labeled ``degrees F'' and the humidity must be labeled ``%''.
Here are the conversion factors and formulas the program must use. Note that you MUST use these EXACT conversion factors and formulas, even though you may know of more accurate values. You MUST also use preprocessor macros (symbolic constants) to define any conversion factors or special constants used in the program.
where TC is temperature in degrees Celsius and TF is temperature in degrees Fahrenheit
1 inch of mercury = 33.86389 millibars
1 millibar = 0.02953 inches of mercury
1 mile = 5280 feet
1 knot = 1.15 miles per hour
Dew point temperature and relative humidity are actually related by a complicated calculation involving the portion of air pressure due to the water vapor content of the air, but a good approximation for normal ranges of air temperature is:
where T is equal to the air temperature in degrees Celsius and TD is equal to the dew point temperature in degrees Celsius (NOTE the units of temperature are degrees CELSIUS!)
In this project, you should use
float variables (or expressions)
for quantities which may have a fractional part, and
for whole number quantities. Chapters 2-4 of your text don't discuss how
expressions which contain both
float values are evaluated
(this is covered in detail in a later chapter). In order to avoid any
problems with your calculations, you should realize now that expressions
float values will have a
When writing the expressions for the conversions, be aware that doing the statements in a different order can cause you to get a different answer. For example (52/5200) * 100.0 = 0.0 but (52*100.0)/5200 = 1.0. This is because the 52/5200 is calculated as an integer value since both operands are integer. The answer is actually 0.01, but because it is forced into an integer storage location, only the 0 is stored. Then when it is multiplied by 100.0, the answer is 0.0 because any float times 0 is 0.0. When the second expression is evaluated, the 52 * 100.0 makes it 5200.0 (a floating point number), and then when the division happens, the answer is 1 because there was no truncation of the fractional part. If you have two integers and you want to make sure the result is stored in a float, one easy way is to multiply one of the operands by 1.0 before the other operation is done.
All your C programs in this course should be written in ANSI C, which means they must compile and run correctly with ``cc -std1 -trapuv'' on the OIT UNIX Class Cluster. Even if you already know what they are, you may not use any C language features other than those introduced in Chapters 1 through 4 of your textbook, plus those presented in lecture while these chapters were covered. Note that as a result conditional statements or loops of any type may not be used. Using C features not in these chapters will result in losing credit.
Your program must have a comment near the top which contains your name, login ID, student ID, your section number, your TA's name, and an original description of the action and operation of the program. Do not put your alias in this comment! Your program should be written using good programming style and formatting, as discussed in class and throughout your textbook. For this project, style is considered to consist of:
You may want to skip this section at first, read the rest of the project, and come back to study it carefully when you are about to begin writing your program.
A crucial part of the material to be learned in this course is how to properly develop programs and find the inevitable errors you will make while writing them. This section addresses how to do that. It is not up to the instructional staff to find every error in your program; you need to learn how to find and fix most of them for yourself. If you have tried the techniques below and have still not been able to find or correct a problem, bring a printout of your program (plus printouts of any compiler errors or execution results) to our office hours and we will be able to help you.
Many people like to write their whole program, or at least have a good outline and idea of what it will look like, before sitting down to type any of it in. That's fine, but it is absolutely essential that you never type in more than a short part of your program without stopping to test what you have so far. You should stop and compile your program, run it on sample input, and verify that it works correctly so far before going on to enter the rest of the program! Of course, as each intermediate stage the part of the program you have entered will obviously not solve the whole problem, and it must at least be a complete and valid C program, but you will find that testing your project at each stage of development will insure you can find and fix any errors more quickly and easily.
For instance, even with a relatively short program like this one you might enter or implement it in steps as follows:
printfstatements to print the values which were read, to make sure these values were read and stored correctly. If not, correct your program before going on!
In fact, you may want to break each of these steps up into smaller steps- to add statements to print only part of each output section at a time.
Many programs can be developed with equal ease in different orders. The specific steps followed are not important; what is crucial is that you stop and compile and test your program after each one.
}). Make sure that there is a closing brace to match the
mainfunction's opening brace. Indenting statements between braces in a readable manner will assist in this task.
Printf) This means you have
misspelled the name of one of the standard library functions
scan, etc.). Every program component must be
spelled exactly, and even one incorrect character will cause
your program to fail to compile. Check every call to these
library functions carefully.
You probably forgot either the opening or closing double-quote
mark in one of your
The cc C compiler requires that a source file's name end in ``.c''. That's a lowercase ``c'', as in a filename like ``proj1.c''. If your program's filename isn't in that format you must rename it.
It is inevitable that many, if not most or all, of your programs will fail to work correctly as initially written. A few simple strategies can help:
printfstatements to your program to print out the values of variables and calculations. Essentially, this lets the computer trace your program for you. If the
printfstatements show that your variables or expressions don't contain or produce the values you think they do then that's a clue to what's wrong. Using debug
printfstatements you can narrow the problem down and determine which variables or expressions don't have the proper values, and then look at those more closely.
floatvariable which has never been given a initial value and contains a garbage value. To check for the first case, add debug
printfstatements before every division printing the value of the denominator. To check for the second one, check carefully that all your
floatvariables have initial values or that values are assigned to them or read into them before they are used in calculations.
scanf. See your lecture notes where this was discussed, or look at your textbook on pages 39-40.
scanf. See your class notes, or carefully reread pages 39-40.
Readable code is important in the real world because most of the programmer's time is spent rewriting or modifying code that already exists - not writing code from scratch. To make your code readable, be sure to use descriptive variable names (English words or their abbreviations), indentiing (so that you can tell what statements are dependant on others), vertical whitespace (blank lines between sections) and comments for the person reading the code. Even though in this class you will not be rewriting someone else's code - anyone of the instructional staff who reads your code will be able to do so much quicker and the grader will be much more likely to be able to follow your code if you make it readable right from the start.
Remember that the vertical spacing (what appears on each line) is up to you as you type. Emacs does not do a word wrap - so if there is a very long line, you should press the enter key to wrap it to the correct position on the next line to make the code as readable as possible.
Keep one or two backup copies of your program saved under different filenames or in different subdirectories of your account. Before making any major changes to your program, copy it to a new backup file with a different name. This will save you a lot of time if you accidentally delete your file, or if it turns out that your changes were incorrect and you want to quickly revert to the previous version without having to undo all of your modifications by hand.
Always start all your projects as soon as they are assigned! If you end up having a problem which you can't solve on your own you will have plenty of time to come to office hours for help. If you wait until right before a project is due and you run across such a problem it's too late to get help without having to submit your project late and lose credit.
Your project must be electronically submitted by the date above, before 11:00 pm, to avoid losing credit as indicated on the syllabus. No projects more than two days late will be accepted for credit without prior permission or a valid medical excuse, as described on your syllabus. Only the project which you electronically submit, according to the procedures provided, can be graded; it is your responsibility to test your program and verify that it works properly before submitting. Lost passwords or other system problems do not constitute valid justifications for late projects, so do not put off working on your program or wait to submit it at the last minute!
Turn in your assignment using the ``submit'' program provided by your instructor. You are to submit only the .c file containing your source code, not the executable version of your program!
If your source code was in a file named ``converter.c'', submit would be run to turn it in as shown:
% submit 1 converter.c
In order to execute either submit command above you must have previously run the ``setup'' command in your instructor's posting account, as described in discussion section and mentioned again below. If you do not see a message saying your submission was successful then your project was not turned in. Try again, or come to office hours for assistance.
Before you submit your project, you must exactly follow the specific submission checklist in the ``Testing a project before submitting'' handout separately posted by your instructor!
Here is a sample output, assuming the executable version of the program is in a file named ``wizard''. Underlined text is typed in as input when the program is run, while everything else is written as its output. The output would vary if different values were entered for any of the underlined input values. Be sure to test your program against a variety of inputs, so you are sure it works in all circumstances!
Welcome to "Weather Wizard" Unit Converter!
Please enter values in `ENGLISH' units:
Enter Fahrenheit temperature: 86
Enter pressure in inches: 29.53
Please enter values in `METRIC' units:
Enter Celsius temperature: 20
Enter pressure in millibars: 1000
Enter miles and feet traveled: 1 1000
Enter number of minutes and seconds elapsed: 1 28
Enter Fahrenheit air temperature and dew-point temperature: 86 68
English to metric conversion
Temperature: 86 Fahrenheit 30 Celsius
Pressure: 29.53 inches 1000 millibars
Metric to English conversion
Temperature: 20 Celsius 68 Fahrenheit
Pressure: 1000 millibars 29.53 inches
Wind calculator results
Wind: 71.36 feet/sec 49 mph 42 kt
Humidity calculator results
Temperature 86 degrees F Dew point 68 degrees F Relative humidity 55%
IT IS THE RESPONSIBILITY, UNDER THE UNIVERSITY HONOR POLICY, OF ANY STUDENT WHO LEARNS OF AN INCIDENT OF ACADEMIC DISHONESTY TO REPORT IT TO THEIR INSTRUCTOR.