command line arguments in java

[mira88]

Hi, I'm new to java and would like to know how to take several command line arguments and sum them . I have done so for two numbers- but don't know how to go on. Thanks

  
public class TwoNumbers {
     public static void main(String args[]){
    	 
    	 int first_number = Integer.parseInt(args[0]);
    	 int second_number = Integer.parseInt(args[1]);
    	 int addition = first_number + second_number;
    	 
    	 if(args.length>2){    		 
    	 }
    	 System.out.println("The sum is :"+ addition);
     }
}

[blazedaces]

Hi, I'm new to java and would like to know how to take several command line arguments and sum them . I have done so for two numbers- but don't know how to go on. Thanks

  
public class TwoNumbers {
     public static void main(String args[]){
    	 
    	 int first_number = Integer.parseInt(args[0]);
    	 int second_number = Integer.parseInt(args[1]);
    	 int addition = first_number + second_number;
    	 
    	 if(args.length>2){    		 
    	 }
    	 System.out.println("The sum is :"+ addition);
     }
}

Um... Thought your problem was that didn't work.

Make a for loop with (int i = 0; i < args.length; i++) { /*declare total=0 earlier*/ total+=Integer. parse(args[i])

Does that help?

-blazed

[mira88]

What errors are you getting when trying to compile this?

-blazed

Im not gettin any errors ,but this programm does the addition for only two numbers and i want to know how to add for three or five or whatever numbers

[blazedaces]

Im not gettin any errors ,but this programm does the addition for only two numbers and i want to know how to add for three or five or whatever numbers

Note: message copied so user knows I posted.
Um... Thought your problem was that didn't work. Didn't read completely, sorry.

Make a for loop with (int i = 0; i < args.length; i++) { /*declare total=0 earlier*/ total+=Integer. parse(args[i])

Does that help?

-blazed

[mira88]

yea it worked , thanks so much

[blazedaces]

yea it worked , thanks so much

I just want to know, for your sake, you understand why that worked right? I mean you even used args.length with your if-statement. So you're slightly familiar with arrays, right? If you want to iterate through them, use a for-loop (there are other ways).

"As the great Andrew Martin once said, 'One is glad to be of service'."

-blazed

[mira88]

Well the way i understand it , as long as the length of the argument is greater than 0 initially, then the sum of the numbers will take place and then i will be increased by 1. Right?

[blazedaces]

Well the way i understand it , as long as the length of the argument is greater than 0 initially, then the sum of the numbers will take place and then i will be increased by 1. Right?

Yes, good. It's just, we're not supposed to just "give" you the answer, but rather guide you through it (my bad).

Either way, good luck with java coding...

-blazed

[mira88]

Thanks anyway, I have another question .I'm trying to do the same with multiplication and in my code I'm saying that if the argument length is greater than two then my multiplication should work - but its not. Can I initialise i with a 2 ,cause that is what I've done. I think I'm doing something wrong. Maybe you should guide me through :)

  
 public class MultiplyMoreNumbers {
	public static void main(String args[]){
		int multiply= 0;
		
		for(int i=2;i<args.length;i++){
			multiply = multiply*Integer.parseInt(args[i]);
		}
		System.out.println("The product is " + multiply);
	}

}

[blazedaces]

Thanks anyway, I have another question .I'm trying to do the same with multiplication and in my code I'm saying that if the argument length is greater than two then my multiplication should work - but its not. Can I initialise i with a 2 ,cause that is what I've done. I think I'm doing something wrong. Maybe you should guide me through :)

  
 public class MultiplyMoreNumbers {
	public static void main(String args[]){
		int multiply= 0;
		
		for(int i=2;i<args.length;i++){
			multiply = multiply*Integer.parseInt(args[i]);
		}
		System.out.println("The product is " + multiply);
	}

}

Sorry, I laughed a little bit when I read it. I can completely understand the mistake.

You're actually making two mistakes.

This is what I suggest. If this happens again (if your output ends up 0 no matter what), write out the process on a piece of paper, just like I'll show you right now:

Ok, I want the args to be, let's say 1,2,3,4,5
Ok, so file starts.

multiply = 0  Got it.

for 2 to 4 times I will do this: multiply times integer of the corresponding arg {
2:  mutiply = multiply * arg[2] = 0 * 3 = 0;
3:  mutiply = multiply * arg[3] = 0 * 4 = 0;
4:  mutiply = multiply * arg[4] = 0 * 5 = 0;
}

Ok, now print "The product is " + multiply which will print: The product is 0

What do you think you should change? One thing at a time.

Hope I'm guiding you through this well enough,

-blazed

[mira88]

Well, first I think i need to change my definition of multiply and secondly i have to redefine my for loop. Will do that and see if there is a change.

[mira88]

Hi I finally got it!! And it works , here is the corrected code .

public class MultiplyMoreNumbers {
    public static void main(String args[]){
        int multiply= 1;
        
        for(int i=0;i<args.length;i++){
            multiply = multiply*Integer.parseInt(args[i]);
        }
        System.out.println("The product is " + multiply);
    }
 
}

Thanks soooo much

[JosAH]

Hi I finally got it!! And it works , here is the corrected code .

public class MultiplyMoreNumbers {
    public static void main(String args[]){
        int multiply= 1;
        
        for(int i=0;i<args.length;i++){
            multiply = multiply*Integer.parseInt(args[i]);
        }
        System.out.println("The product is " + multiply);
    }
 
}

Thanks soooo much

That algorithm assumes that the multiplication of zero numbers equals one (1).

kind regards,

Jos ( <--- nitpicker ;-)

[mira88]

Oh I guess thats wrong then.

[JosAH]

Oh I guess thats wrong then.

Don't let me confuse you; the sum of zero numbers is assumed to be zero which
everyone finds acceptable; so why shouldn't the product of zero numbers be
equal to one then? Although not many people realize the assumption.

Your solution is fine as it is; don't let a nitpicking sloppy mathematician confuse you ;-)

kind regards,

Jos