I have the following java code and I need help in a for loop that searches in an array for a certain element

Question

I have this code. It won t work in Sololearn console and it requires multiple inputs, so please check it in your console (jdk)

I have a list of things i can do:
0 exit
1 create student
2 check if there are any students in the class whose nrMatricol is equal with the user's input

The problem is at 2.
I search for an nrMatricol (example "22222") and enter.
the "for" loop goes on and i get 19 "no"'s, because there are 19 null elements.
But, even if "22222" exists (which does, because there are 5 existing students), nothing gets written (line 94).
Help pls, am I writing something wrong? I think i did all the conversions to string.

https://code.sololearn.com/c6Icu2iuHb4g

Answer 1

🍇 Alex Tușinean 💜

Don't compare string with ==

use equals method

if((AIA.lista_studenti[k].getNrMatricol()).equals(nrMatricolCautat))

Answer 2

🍇 Alex Tușinean 💜

I think Tapabrata Banerjee [Less Active] explained well.

Answer 3

Wait, but what is == used for in java? I though == is for comparison

anyway, your solution works. Thanks a lot! I would have never guessed the == was the issue.

Answer 4

🍇 Alex Tușinean 💜

== compares value as well as reference so in Java String is a reference type so two String cannot have same reference that's why == is not preferable for String comparison.

1, 2, 3 are value type so that is not wrong.

Answer 5

A͢J - S͟o͟l͟o͟H͟e͟l͟p͟e͟r͟ does that mean that where I compared selectie with 0 1 and 2 is also wrong?