Passing an array of arguments in Java

Question

I started learning Java yesterday and I am now trying to create a program that sums a list of integers in the form of strings. When I try to compile and run the program in Eclipse I get the following error. "The method doSomething(String[]) in the type Calculator is not applicable for the arguments (String, String)". Sorry for that my code looks all messed up. I didn't figure out how to make all of the code in a different font. I got the "inspiration" of trying to pass multiple arguments to a function from the main class since it seems to be working there. I have tried to instead write (String ... arguments) which seems to work fine.

public class Sum {

    int doSomething(String[] arguments) {
        int sum = 0;
        for (int i = 0; i < arguments.length; i++) {
            sum += Integer.parseInt(arguments[i]);

        }
        return sum;

    }

    public static void main(String[] args) {
        String var = "1";
        System.out.print(doSomething("531", var));
    }

}

Well yes, the doSomething method in your main method has 2 strings in it, but it requires an array to be happy, you need to either change that line and give it an array, or change your parameters, could you describe what it is you are trying to do here? — DreadHeadedDeveloper
– DreadHeadedDeveloper, Commented Oct 23, 2014 at 14:14
First of all, thank you for improving my post. I'll have a closer look at your change soon. I'm trying to combine what I've learned so far. I want to write a function which can take as many numbers as strings and possible, then convert the strings to integers and finally return the sum of the values of the strings. — Ludwwwig
– Ludwwwig, Commented Oct 23, 2014 at 14:17
Also, doSomething is called as a static method. however it is not one. Add the static keyword to it to make it work. — Frunk
– Frunk, Commented Oct 23, 2014 at 14:18

jhamon · Accepted Answer · 2014-10-23 14:16:22Z

3

You need to initialize a new String array with your values:

doSomething(new String[]{"531", var});

By doing

doSomething("531", var)

You are calling doSomething with 2 String arguments while it's expecting a single argument: String array

answered Oct 23, 2014 at 14:16

jhamon

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4 Comments

Ludwwwig Over a year ago

I'm new to the way of thinking in Java, with objects and such, and it seems different to what I'm used to in Python and C++, but so far I enjoy it! If I understand your code correct, you are creating a new Object of the String type and then filling it with 2 values. Could I write doSomething(new String[2]{"531", var}); instead if I know that I will be passing only 2 arguments, like in this case?

DreadHeadedDeveloper Over a year ago

@Ludwwwig it's redundant, the number of values is determined by the system counting up how many values you gave it

Frunk Over a year ago

@Ludwwwig the [2] is not needed because the compiler already knows you are passing 2 items. So the size will be 2.

jhamon Over a year ago

you are creating a new Object of the String type. No, it's a String[] so it's an array object.

injecteer · Accepted Answer · 2014-10-23 14:19:34Z

1

you might want to use this form:

int doSomething(String... arguments) {
    int sum = 0;
    for (int i = 0; i < arguments.length; i++) {
        sum += Integer.parseInt(arguments[i]);
    }
    return sum;
}

then you can call:

doSomething( "aa" );
doSomething( "aa", "bb" );
doSomething();

answered Oct 23, 2014 at 14:19

injecteer

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Comments

DreadHeadedDeveloper · Accepted Answer · 2014-10-23 14:20:10Z

0

public class Sum {

   static int doSomething(String[] arguments) {
      int sum = 0;
      for (int i = 0; i < arguments.length; i++) {
         sum += Integer.parseInt(arguments[i]);

      }
      return sum;

   }

   public static void main(String[] args) {
      String var = "1";

      String s[] = {"531", var};

      System.out.print(doSomething(s));
   }

}

This way, you have the values stored into an array s , and then you pass that array, problem solved!

answered Oct 23, 2014 at 14:20

DreadHeadedDeveloper

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1 Comment

DreadHeadedDeveloper Over a year ago

I also added static to your 'doSomething' method so that it would work cuz right now, it isn't compiling

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