![Example Program : command-line arguments
class CommandLine {
public static void main (String args[]) {
for(int i=0; i<args.length; i++) {
System.out. println(“ args [ ”+ i “ ] : ”+args[i]);
} // end of for
} // end of main
}// end of class
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![Example Program : Command-line Arguments contd..
• Try executing the program as shown here
• Java CommandLine this is a test 100 -1
•When you do, you will see the following output:
Output :
args[0] : this
args[1] : is
args[2] : a
args[3] : test
args[4] : 100
args[5] : -1
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![Example Program
• Usage of command-line arguments that needs conversion
class CommandLine {
public static void main (String args[]) {
int a = Integer.parseInt(args[0]);
int b = Integer.parseInt(args[1]);
int c = a + b;
System .out. println(“ sum of the ”+ a + “ and ” +
b+ “ is :”+ c);
} // end of main
}// end of class
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Command line arguments.21
- 1. Usage of command-line arguments http://improvejava.blogspot.in 1 1
- 2. Objective On completion of this period, you would be able to know, • The usage of command-line arguments 2 http://improvejava.blogspot.in
- 3. Recap • In the last class we discussed • The String class • Constructors of String class • Methods of String class http://improvejava.blogspot.in 3 3
- 4. Usage of command-line arguments • How to pass information into a program when you run it? • This is accomplished by passing command-line arguments to main() • A command line argument is the information that directly follows the programs name on the command-line when it is executed http://improvejava.blogspot.in 4 4
- 5. Usage of command-line arguments contd.. • To access command-line arguments inside a java program is quite easy • They are stored as Strings in the String array passed to main() • For example, the following program displays all of the command-line arguments that it is called with 5 5
- 6. Example Program : command-line arguments class CommandLine { public static void main (String args[]) { for(int i=0; i<args.length; i++) { System.out. println(“ args [ ”+ i “ ] : ”+args[i]); } // end of for } // end of main }// end of class http://improvejava.blogspot.in 6 6
- 7. Example Program : Command-line Arguments contd.. • Try executing the program as shown here • Java CommandLine this is a test 100 -1 •When you do, you will see the following output: Output : args[0] : this args[1] : is args[2] : a args[3] : test args[4] : 100 args[5] : -1 7 7
- 8. Usage of command-line arguments • All command-line arguments are passed as strings • You must convert it into desired format, using wrapper classes 8 8
- 9. Example Program • Usage of command-line arguments that needs conversion class CommandLine { public static void main (String args[]) { int a = Integer.parseInt(args[0]); int b = Integer.parseInt(args[1]); int c = a + b; System .out. println(“ sum of the ”+ a + “ and ” + b+ “ is :”+ c); } // end of main }// end of class 9 9
- 10. Example Program contd.. • Try executing the program as shown here, • Java CommandLine 10 20 • When you do, you will see the following output Output : sum of the 10 and 20 is : 30 http://improvejava.blogspot.in 10 10
- 11. Discussion • What are the differences between command line arguments in C and Java ? C Java Number of One less than the Equal to actual arguments actual number number Type of Character array String arguments http://improvejava.blogspot.in 11 11
- 12. Summary • About command line arguments • Usage of command line arguments http://improvejava.blogspot.in 12 12
- 13. Quiz 1. Command-line arguments are passed from a. calling method b. command prompt c. from JVM d. from operating system http://improvejava.blogspot.in 13 13
- 14. Quiz contd.. 2. Command-line arguments are stored in a. Variables b. Actual parameters c. int parameter d. String array http://improvejava.blogspot.in 14
- 15. Frequently Asked Questions 1. Explain the use of Command-line arguments with an example program? http://improvejava.blogspot.in 15 15
- 16. Assignment 1. Write a program in Java that takes command-line arguments and display how many number of parameters passed 2. Write a program in Java that takes command line arguments and that searches for a give is present in command-line arguments 3. Write a program in Java that takes command line arguments and print the parameter in String array in reverse order http://improvejava.blogspot.in 16