Trouble trying to skip iteration of a while loop in Java

Question

I'm new to Java (and to programming in general). I have a program that is supposed to run a method on two variable strings, but only if the strings are the same length and are not identical.

I've tried using

while(i < n){
    if (string1.length() == string2.length() && string1 != string2){
        compare(string1, string2);
        i++
    }
}

but it still runs the compare method even if the strings are identical.

I've also tried using

while(i < n){
    if (string1.length() == string2.length(){
        if (string1 == string2){
            continue;
        }
        compare(string1, string2);
    }
    i++
}

but this also still runs the compare method regardless of whether or not the strings are identical.

Is there an issue with my formatting, or perhaps misused keywords? Thanks!

I'd be very surprised if `compare` will run if strings are really identical (in case using the same value via `string1 = string2`) — Alexei Levenkov, Oct 31 '14 at 05:55

score 1 · Answer 1 · answered Oct 31 '14 at 05:49

1

This string1 != string2 does not test String value equality, only reference equality. You need !string1.equals(string2). Or your while would need to be something like,

if (string1.equals(string2)) {
  // ... they're equal.
}

It is also worth noting that the two String(s) must have the same length() or equals() would return false.

answered Oct 31 '14 at 05:49

Elliott Frisch

198,278
20
158
249

you are 25 sec faster – amit bhardwaj Oct 31 '14 at 05:50

score 0 · Answer 2 · answered Oct 31 '14 at 05:50

0

Using equals() method instead of ==. Double equal sign can't use in object compare.

answered Oct 31 '14 at 05:50

Kevin Huang

69
5

score 0 · Answer 3 · answered Oct 31 '14 at 05:50

Change

if (string1.length() == string2.length() && string1 != string2)

With

if (string1.length() == string2.length() && !string1.equals(string2))

== check the reference equality. when you come in to String variables they have two different reference in the heap while having same value. To check the equality of values you should use equals()

Trouble trying to skip iteration of a while loop in Java

3 Answers3