Lab01

LAB1 (20pts) - Command Line Compilation and the CLion Environment

Purpose: This lab will familiarize you with compiling C++ programs from the command line and with using the CLion environment.

NOTE: Put your name (as comments) at top of all .cpp and .h files.

PART1: Create and compile your first C++ program using the command line compiler. [The steps below assume you are using MacOS. Differences for Windows are listed where needed.]

In order to run the following program, follow the instructions for command line compilation:
1. Create a folder ( Lab1CommandLine) to contain your source code and executable.
2. Open a terminal wondow (Applications->Utilities->Terminal, or locate the Terminal window with the Spotlight search). [In Windows open a Comman window.]
3. Navigate to the folder you created on the Desktop. You will do this within the Command Prompt window by using the "cd" command (cd stand for change directory). The easiest way to do this is to type "cd" at the command line and then drag your folder onto the Command Prompt window. You may see something similar to:
4. cd /Users/svisa/Desktop/Lab1CommandLine
5. You can list the contents of your current directory within the Command Prompt window by typing "ls" (ls stands for list directory) [or "dir" in Windows].
6. Create your source program using a text editor (not MS Word). Copy and paste the code below, and save the source program as Lab1.cpp. Be sure to save the file in the folder you created on the Desktop (use Save As.. option).
7. To compile a single C++ source file, type in the following command within the Command Prompt window:
  g++ -o Lab1 Lab1.cpp
  NOTE: if OS cannot find the g++ compiler, type in your Terminal sudo, then try compiling again. Another fix is adding the path to MinGW/bin to the PATH Environment Variable (Microsoft Windows).
8. Here, g++ invokes the C++ compiler, the -o option specifies the name of the created object file (the executable is Lab1 for this example), and Lab1.cpp is the source file to be compiled. [Windows sometimes does not find the location of the g++ compiler. In this situation you may (1) either open the Terminal associated with MinGW by typing in "MinGW" in command bar and then slecting "open in terminal"; or (2) open the terminal from CLion.]
9. If your source file compiles without errors then you should find an executable file located in your directory. You can check this by typing "ls" to list the directory contents.
10. Run your program by typing ./Lab1 at the Command Prompt. [In Windows you run it by simply typing "Lab1.exe".]
11. Note: a compilation comand such as g++ Lab1.cpp creates an executable named by default a.out.This executable can be run in the command window with ./a.out.

/*
     PROJECT: Lab1 assignment on command line compilation
     FILE: main.cpp
     PURPOSE: To illustrate the use of command line compilation
     PROGRAMMER: S. Visa
*/

#include <iostream>   //include the input/output classes

using namespace std;  //use the standard C++ namespace so names do not have to be fully qualified

int main()
{
     cout << "Hello World!\n";  //print Hello World! to the terminal followed by a return
     
     cout << "Enter an integer to terminate the program:";                                              
     int dummy;
     cin >> dummy;                              //type an integer and return to exit the program - this makes the executable "wait"
                                                // so we can see the program output
	 return 0

}

Ask questions if you run into problems.

Make the following changes to your first program, compiling and executing after each modification.
1. Comment out the "Hello World! output statement.
2. Declare three integer variables with the initial value of 0.
3. Read three integer values from the keyboard and store in the integer variables declared in 2).
4. Print the three integer variable values of part 3) to the terminal with an appropriate string message.
5. Compute and print the sum of the three integer variable values of part 3) to the terminal with an appropriate string message.
6. Compute and print the average of the three integer variable values of part 3) to the terminal with an appropriate string message.
7. Find and print the largest of the three integer variable values of part 3) to the terminal with an appropriate string message.
8. Find and print the smallest of the three integer variable values of part 3) to the terminal with an appropriate string message.

Ask questions if you run into problems. (A possible output sample of your program can be found here.)
Create a snapshot of your output similar to the one shown in the line above. Name it part1.png and submit it inside your zipped folder Lab1CommandLine.zip as expalined at the end of this lab. [Make sure Lab1.cpp and the pictures are in the zip folder.]
Note:
1) To create a snapshot in Mac OS, click Command+Shift+4, and select the area you want to save as png (is a picture format). You will find your selection saved as a png file on Dektop.
2) In Windows you may use the print screen key PrtScrn to capture an image of your entire desktop. Then you can paste it in Paint and save it as a png or jpg picture.

PART2: Using CLion.

1. Create a new CLion project.

To open CLion, go to Applications -> CLion, or use the Spotllight search.

To create a new project, click "New project"
Name it (at Location) Lab1CLion
(Leave the type of project as the default "C++ Executable")
Select language standard as C++14
Click "Create" button

2. Hello, World! (output)

In a new project, CLion creates a default C++ file, main.cpp (find it in the left panel), with a main function. When you run a C++ program, it starts executing at the main function. Replace the existing code in main with this equivalent code (copy and paste):

#include <iostream>
using namespace std;

int main () {
cout << "Hello, World!" << endl;
return 0;
}

Click the Run button (see the gree triangle at the top banner). The program should run, and it should print Hello, World! If not, ask for help.

3. Hello, <your name>! (input)

Now you’ll make the program read in a string of text from the user and print it. Add the following statements at the beginning of the main function (copy and paste):

string name;
cin >> name;

Replace the cout statement with this:

cout << "Hello, " << name << "!" << endl;

Run the program. Does it work?

Add a statement that tells the user to enter her/his name.

4. Count-down function (functions, loops)

Now you’ll add a function to your program that counts from a maximum number down to 0. Add the following code just before the main function:

void countDown(int max) {

}

This is a function called countDown. Between the curly braces, write code that prints the integers from max down to 0 (inclusive).

At the beginning of the main function, add the following call to countDown:

countDown(5);

Run the program. Does it work?

Move the countDown function down after the main function. Run the program. Does it work?

Just before the main function, add the following function declaration:

void countDown(int max);

Run the program. Does it work? If not, ask for help.

5. Count-down in a library (functions, .h and .cpp files)

Now you’ll move the countDown function into a pair of files called a library.
Right click on Lab1CLion (located in the left-most panel, above main.cpp) and select New -> C/C++ Header File. Name the new file as count.h.

Move the declaration of countDown (the part before main) into count.h.

Similarly (by using New -> C/C++ Source File), create a file named count.cpp (if necessary, uncheck the box "Create an associated header"). Move from main.cpp the definition of countDown (the part after main) into count.cpp. In count.cpp, somewhere before the countDown function, add the following:

#include "count.h"
#include <iostream>
using namespace std;

In main.cpp, somewhere before the main function, add the following:

#include "count.h"

Run the program. Does it work?

Note: Now inspect the CMakeLists.txt file that CLion created for you; in the add_executable line you will see all the files included in your project. Later in this course you will learn to customize this line so that it includes different files for different runs of the same project. For instance, if in a C++ project you have two files each having a main() functions, the project will not compile; but by editing this line to include only one of the two files, your project will compile and execute. We will practice this knowledge later during class time.

6. Practice problems

For all problems: solve them using the model above (i.e. appropriate entries in count.h and count.cpp) and add code to the main function that allows you to test your functions. (A possible output sample of your program can be found here.) Create a snapshot of your output similar to the one shown. Name it part2.png and submit it as expalined at the end of this lab.

(P1) Write a function that takes 3 arguments, all real numbers, and returns their average.

(P2) Write a function that takes 2 arguments of type bool and returns true if and only if exactly one of them is true.

(P3) Write a function that continues to read and display a character until "Y" character is entered.

(P4) Write a function that takes 1 argument, an integer, and returns the factorial of that integer. For example, given 4, it should return 24 (4! = 4 * 3 * 2 * 1). What if the argument is negative? (Your function should return 0.) What if the argument is 0?

Submit your project folder in the following way:

Zip your Lab1CLion folder (Control-click on the folder and select Compress). Please submit zip, not rar archives.
Upload on Moodle the zipped files Lab1CommandLine.zip from part 1 and Lab1CLion.zip from part 2. (Note: if link does not seem to work, try "Right-Click" and "Open-in-New-Window".)