Cara Program dengan Eclipse
This set of introductory exercises are intended to introduce you to programming C++ in the Eclipse integrated
development environment.
PART 1: Using an Editor and Compiling Your First Program
1. Log on to a Linux Workstation and open a terminal window. You can open a terminal windows by selecting
“Terminal” from the “System Tools” menu. You may want to make a shortcut for a terminal on your dekstop.
2. Type “mkdir csc121” to create a new directory for your CSC121 assignments. Remember, Linux is casesensitive! Type “ls” to list all the files in your home directory. Change directories to the new one you created
by typing “cd csc121”.
3. Start the gedit program by selecting it from the program menu or by typing “gedit” from within a terminal
window. Gedit is a general purpose text editor (like Notepad) that you can use to edit the source code of your
programs.
4. After you start gedit click the New icon to open a new file. Next, click Save to give your file a name. Select the
csc121 directory and then type a name for your source file such as program1.cpp (note that C++ program
source files typically end with a .cpp). This will create a new file that you can begin editing.
5. Type the following source code for your C program. Note that all C programs should start with some header
comments that identify the programmer and a description of what the program does. You should also observe
that the “.cpp” extension indicates to gedit that your file is a C++ program and syntax highlighting is provided to
make your code more readable.
/* My first CSC121 Assignment
This program prints a friendly greeting */
#include <iostream>
#include <string>
using namespace std;
int main()
{
cout << "Please enter your first name: " << endl;
string firstName;
cin >> firstName;
cout << "Welcome to the world of C++, " << firstName << endl;
return 0;
}
When you have finished editing save your file. Don't worry if you don't understand what you have just entered.
6. To compile your program, return to the terminal window and type the compile command at the prompt as shown
below:
g++ -Wall program1.cpp -o program1
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Notes:
Before tpying this command, ensure you are in the same directory as your source file
g++ invokes the GNU C++ compiler
-Wall turns all warnings on
program1.cpp is the name of the source file
-o program1 specifies the name of the compiled output file
If the compiler detects any errors or warnings, they will be reported. If there are any errors or warnings, you
will have to return to the editor to make any corrections as necessary. Be careful - one forgotten semi-colon is
enough to cause an error!
7. Once your editing and compiling are complete and no warnings or errors are generated, a new program file will
appear in your directory (type “ls” to see a list of files). You can run your program in a terminal window by
typing:
./program1
Homework submissions require a log of your program output. One way to do this is to use the script utility. To
begin logging your output to a file, return to a terminal window and type “script” . The script program will log
all the following output to a file called typescript by default. Run your program again and then type exit to end
the script program and stop logging. To view the contents of the script file type:
cat typescript
Note that if you run script again it will overwrite the contents of the previous typescript file. To prevent the file
from being overwritten, simply copy the typescript file to another filename using the cp (copy) command:
cp typescript part1script
Include a printout of the script output for this program when you hand in the assignment. You can print the
script output by opening the file in gedit or copy and paste it into a word processing document. For more
information on the script program type: man script
8. Recompile the program without the -o program1 option. Use the ls command to view your directory.
Question A: What is the default name given to the output program if the “-o” option is not specified?
9. Edit the source file to remove the semi-colon from the cout statement and then recompile. Next, replace the
semi-colon and remove one of the curly braces “{“ or “}”.
Question B: What error messages does the compiler report due to a missing semi-colon? What error
messages are reported with a missing curly brace?
10. Expand the program by adding lines to print out your name and Redeemer e-mail address. Recompile and run
the program and log the output once again and submit this with your homework.
Part 2: Using the Eclipse Integrated Development Environment (IDE)
Modern software development is often done using an Integrated Development Environment (IDE). IDEs provide a
graphical environment for editing, compiling and debugging code. In this tutorial you will use the Eclipse IDE.
11. Launch Eclipse by typing “eclipse” inside a terminal window or by clicking in the Eclipse icon in the menu.
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12. To start coding a new program, start a new project by selecting File/New/Project from the menu. From the
wizard menu under C++, select “Managed Make C++ Project”. Click “Next” and enter “Assignment1a” as the
project name. You should avoid project names that contain spaces or other non-alphanumeric characters!
Click “Next” and ensure that the project type is “Executable (Gnu)”. Click “Next” and Click the C/C++
Indexer tab, ensure “Enable C/C++ Indexing” is selected. Click “Finish” to finish setting up the project.
13. Create a new C++ source file in the project by clicking on the following icon: A dialog box will open
prompting you to enter a source file name. Enter the name “addition.cpp” (recall that C++ source files should
have a “.cpp” extension). An editor window will appear where you may enter the following source code. Note
that the editor uses syntax highlighting and that it automatically ensures that your code is indented properly.
/* My first CSC121 Assignment
Name: your name
This program sums two numbers and prints the result to the display.
*/
#include <iostream>
using namespace std;
int main()
{
int x,y,sum;
cout << “Enter the first number: ” << endl;
cin >> x;
cout << “Enter the second number: “ << endl;
cin >> y;
sum = x+y;
cout << x << “ + “ << y << “is equal to “ << sum << endl;
return 0;
}
When you are done entering the program, be sure to click the save icon which will also compile your project.
Question C: Try introducing errors in your program (such as removing a semi-colon) and click “Save”. How
does Eclipse help you to identify and locate errors in your program?
14. Compile and run the program by selecting Run from the Run menu. In the wizard dialog which appears, select
"C/C++ Local Application" from the list of Configurations, then click the New icon. Click on the
“Assignment1a” project and then click on “Search Project” to locate your executable file. Next, click on the
Debugger tab and select the “gdb Debugger” from the drop-down menu. Click on “Apply” and then click
“Run”. Once the run configuration has been setup properly, you can run the program again by simply clicking
the run icon . Note that the output from the program will appear in a console window which appears
below the edit window. If your program prompts user input, you will need to click in this window to enter any
program input. Hint: the resulting output can be copied using the right mouse button and pasted into a
document. This can be used to provide a copy of your runtime output which must be included as part of your
homework submission.
15. Debugging is a part of the process of programming. One way to debug code is to use a special debugging tool
that allows you to see what is going on inside your program while it executes. The Eclipse IDE uses a powerful
debugger called gdb (the GNU debugger) which can be used to step through your code to find errors.
Practice using the debugger with the code you wrote in the previous step. Instead of clicking the run icon, select
Run/Debug or click the debug icon and a debugging perspective will open in Eclipse. Upon starting, the
debugger will launch your program and stop at the first instruction. Various windows indicate the status of the
program as the debugger is run. One of the windows in the middle of the screen shows your program, highlighting
the next line to be executed. Breakpoints may be set by clicking in the margin beside the line of code where you
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want the debugger to stop. Another window shows the contents of any variables that have been declared. A window
on the bottom shows the output of the program as it runs.
To begin debugging the program, use the following icons:
- Resume execution until a breakpoint is encountered
- “Step over” will single-step by executing the next instruction
- “Step into” will wingle-step into the next instruction, entering into a function if one is present
- Restart execution from the beginning of the program
- Terminate program execution
Start practicing using the debugger by using the “step over” function to single-step through your program and trace
the execution line-by-line. Examine the contents of each of the variables as the program proceeds and runs to
completion. Note that before the variables are initialized, they contain “garbage” values. Set some breakpoints and
run the debugger again. Hint: When done with the debugger, you can return to the editing perspective by clicking
the “Open Perspective” icon in the top right corner and select “C/C++”.
Question D: What is a variable? (Consult your textbook if necessary)
16. Create a new program that modifies the previous program so that the user is asked to enter 3 numbers (x, y, z),
which are then multiplied together (note that the symbol for multiplication in C++ is ‘*’). Note that every new
program will require its own project. After creating a new project, make a source file called multiply.cpp and
enter the code. Run the new program and record the program output. Refer to Chapter 1 in your text for an
introduction to variables and the cin and cout statements.
Remember: You should create a new C++ project for each new program that you write!
Question E: Using the debugger, record the values of the x, y and z variables when program execution begins
and before the data is input from the keyboard. What are the initial values of these variable and where do
they come from?
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