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18. Command Line Arguments In Java

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Command Line Arguments In Java

Command line arguments are the arguments passed at run time to java program. Arguments are used as input for the program. Any number of command line arguments can be passed to the program.
Command line arguments are be received by main method’s string type array, so they are string by default.

Example 1:

/**
 * This program is used for taking input by command line args.
 * @author javawithease
 */
public class CommandLineArgument {
      public static void main(String args[]){
          int num1, num2;
          //check whether any value is entered or not.
          if (args.length > 0) {
           try {
            //parse string values to integer
              num1 = Integer.parseInt(args[0]);
              num2 = Integer.parseInt(args[1]);
 
              System.out.println("Sum of entered numbers = ");
              System.out.println(num1 + num2);
           } catch (NumberFormatException e) {
            //Catch exception if any in parsing.
              System.err.println("Argument must be an integer.");
           }
         }
      }
}

Output:

Sum of entered numbers = 50

Example 2:

/**
 * This program is used for taking any number of
 * input by command line args.
 * @author javawithease
 */
 
public class CommandLineArgument {
      public static void main(String args[]){
            //print all entered values.
            for(int i = 0; i < args.length; i++){
                  System.out.println(args[i]);
            }
      }
}

Output:

20
30

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