Java Output and Method Calls
Learning Objectives:
- Create a new Java project
- Execute (run) a working Java program
- Define and identify Java comments, strings and methods
- Invoke a Java method and pass parameters to a method
- Produce output from a Java program
# Exercise
1 Create a new folder named \YourName\CP1810
2 Launch NetBeans and create a new Java project as an Application in the above folder a. Launch NetBeans
b. Select Java Application
c. Set Project Name to Lab01_Output
d. Set Project Location to the folder \YourName\CP1810\Lab
NOTE Java ignorescomments. There are two types of comments:
- One-line comments begin with a // and continue to the end of the line
- Multi-line comments begin with a /* and end with a */
3 Run the program.
The program should compile and run cleanly with no errors.
But, there is no output
NOTE A String is any text starting and ending with double quotes
4 Modify the initial program as follows (Replace firstnamelastname with your name):
public static void main( String[] args ) { put( "Hello firstnamelastname" );
} public static void put( String text ) {
System.out.print( text );
}
Run the program
NOTE Methods, such as main() and put(), are basic units of execution in Java
- A method can call or invoke another method
- All Java programs begin execution in the method main()
5 Modify main() and run the program with the following change:
public static void main( String[] args ) { put( "Hello firstnamelastname" ); put( "\n" );
}
NOTE Maintain a working program by always running a program after any change. This way at all times, you are one change away from a working program.
6 Modify main() and run the program with the following change:
public static void main( String[] args ) {
1 put( "Hello firstnamelastname" );
2 put( "\n" );
3 put( "How are you?\n" ); }
7 Here is a program trace of the above:
8 Modify main() to print out:
Hello
Firstname
Lastname
How are you?
9 Modify main() to also print:
*
**
***
10 Modify main() to also print:
*
**
***
11 Modify main() to also print:
*
***
*****
12 Create a new Java project named Lab01_Namethat prints a business card with your name bordered by vertical and horizontal stars.
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* firstnamelastname *
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