asked on

program to accept parameters from command line

i'm trying to figure out how this is done in java...

in command, i would like to type in:

java -classpath \documents\location MyClass 1 2 3

which would add the three numbers following the class name.

MyClass is the class name

\documents\location is the class path

1 2 3 would be the parameters

please help

CEHJ

You can get them through the args parameters of main

SOLUTION

CEHJ

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

ASKER CERTIFIED SOLUTION

Mick Barry

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

shpark82

ASKER

how would i check if the args is int or string or float, etc?

for instance, if i put

1 12 123

as my parameters, would it recognize the numbers as

1,1,2,1,2,3?

or

1,12,123?

also what would happen if i put a letter such as 'A' in it for example

1 A 12

should i be checking if any of the args are not int and throw an exception?

CEHJ

The args are space-separated

>>should i be checking if any of the args are not int and throw an exception?

Yes, if that's a possibility

CEHJ

int sum = 0;
if(args.length > 0) {
      for(int i = 0;i < args.length;i++) {
            if (args[i].matches("\\d+")) {
                  sum += Integer.parseInt(args[i]);
            }

      }
}
System.out.println("Sum = " + sum);

Mick Barry

> 1,12,123?

it would recognise it as 3 strings

> should i be checking if any of the args are not int and throw an exception?

the code I posted above will throw an exception if its not a number

int param1 = Integer.parseInt(args[0]);

CEHJ

This would work for floating point numbers too. If you're interested in int/long, cast to int/long:

double sum = 0;
if(args.length > 0) {
      for(int i = 0;i < args.length;i++) {
            try {
                  sum += Double.parseDouble(args[i]);
            }
            catch(NumberFormatException e) {
                  e.printStackTrace();
            }

      }
}
System.out.println("Sum = " + sum);