Error in my Java code

Question

I've got a problem with my Java program. There is an error in my code on line 16 (t = T[i];) which implies an error on line 12. It says :

Syntax error on token "=",VariableInitializer expected after this token.

Could I have some help ?

public class Ngrams {
 public static boolean estPrefixe(String t, String s) {
 int Longs = s.length();
 if (t.substring(0, Longs) == s) {
 return true;
 } else {
 return false;
 }
 }
 public static int nbOccurences(String[] T, String s) {
 int compteur = 0;
 String t = null;
 for (int i = 0; i < T.length; i++) {
 t = T[i];
 if (estPrefixe(t, s)) {
 compteur++;
 }
 return compteur;
 }
 }

• Josh M: Where is line 12 and 16?
• user180100: Please don't compare string using ==, use proper case
• Peter Lawrey: The code compiles fine for me. BTW estPrefix appears to be the same as String.startsWith
• Peter Lawrey: There was a } missing. I may have accedently fixed the code when trying to fix the formatting.
• Makoto: @PeterLawrey: Yeah, you did accidentally fix the code. Give me a moment and I'll fix the formatting.

Answer 1

Notwithstanding the fact that you're comparing Strings with == instead of .equals(), and that a right bracket seems to have gone AWOL, at the end of your program, you're "missing" a return statement in nbOccurences. Even though you have one in the for-loop, if you never enter the loop, you don't return anything.

Move your return statement down one line, outside of the loop instead.

public static int nbOccurences(String[] T, String s) {
 int compteur = 0;
 String t = null;
 for (int i = 0; i < T.length; i++) {
 t = T[i];
 if (estPrefixe(t, s)) {
 compteur++;
 }
 }
 return compteur;
}

Answer 2

The method nbOccurences does not always return an int value. If T is null or empty (length = 0) no value is returned. So you should add another return statement after the for loop.

As others mentioned already you should use equals to compare strings. This however, is not producing a syntax error.

Answer 3

Well there's a serious bug in this line:

if (t.substring(0, Longs) == s) {

This test will always be false, because == compares object references, not values. Change it to:

if (t.substring(0, Longs).equals(s)) {

But the whole method is pointless. Change it to:

public static boolean estPrefixe(String t, String s) {
 return t.startsWith(s);
}

Or just delete the method altogether because it adds no value whatsoever.

• Prizoff: "This test will always be false" - this is not always true. If t and s are the same object than result of this equation will be true. In the same time, yes, topic starter should always use .equals instead of =.