Is there an alternative to args.EQUAL()?

Question

I'm current learning Java and working through a text book.

I have this piece of code given by the book which works bit like a calculator:

int num1= Integer.parseInt(args[0]);
int num2= Integer.parseInt(args[2]);
String msg = args[0] + args[1] + args[2] + "=";

if (args[1].equals("+")) msg += (num1 + num2));
else if (args[1].equals("-")) msg += (num1 + num2));

and so on.

In console you would do something like: java Args 10 + 2

What I want to know is if something like this can work (I haven't managed to make it work yet)

if(args[1] == "-") msg += (num1-num2));

No don't compare String values using `==`. See http://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java — Alexis C., May 04 '14 at 07:27
It is not "args.EQUAL"; it is [`String.equals`](http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#equals(java.lang.Object)) .. — user2864740, May 04 '14 at 07:28
Note that in your example "java Args 10 + 2", `args[0]` is actually "Args". — kviiri, May 04 '14 at 07:29
@kviiri No, it's the name of the class. `args[0]` will be 10! — Alexis C., May 04 '14 at 07:32
@ZouZou, haha, true! I got this mixed up with Python where the first argument is the name of the script being ran. Thanks for correcting me. — kviiri, May 04 '14 at 07:33
@ZouZou It is name of class (just to confirm). Should of mentioned — user3507121, May 04 '14 at 07:33

score 1 · Accepted Answer · edited May 23 '17 at 11:59

1

The equals() method checks the actual contents of the string, the == operator checks whether the references to the objects are equal. Note that string constants are usually "interned" (except the argument values as they are not compile-time constants) such that two constants with the same value can actually be compared with ==, but it's better not to rely on that.

if (string1.equals(string2)) {
    ...
}

Taken from: Java String.equals versus == , with some modifications.

edited May 23 '17 at 11:59

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answered May 04 '14 at 07:29

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Argument values are not interned because they are not compile-time constants. – Ted Hopp May 04 '14 at 07:35

Is there an alternative to args.EQUAL()?

1 Answers1