Check string for specific number [Java]

Question

I'm trying to check a string for a specific number but it doesn't seem to find it.

string = sc.next();

if(string != "-1")
 return 0;

So when I enter -1 into the input, it just continues on without breaking the program. Am I doing something wrong here?

Answer 1

Instead of != you need to use the operator NOT ! and the method equals

So

string = sc.next();

if (!string.equals("-1")) 
   return 0;

Remember infact that the operators == (or !=) check for same (or not same) object. Instead equals method check that the internal value of the string is the same of the parameter.

Answer 2

If you are expecting a number I would read a number.

int num = sc.nextInt();

if (num != -1) return 0;

BTW: When you use == or != for String it compares only the references, not the contents of the Strings.