I need help with this console game

Question

I'm trying to make a console game in java that tells what your number is
It keeps saying your number is 0 at the end and it is not setting variables to any value other than 0

Here it is:

import java.util.Scanner;

class Program {
public static void main(String[] args) {
int a;
int b;
int c;
int d;
int e;
int number;
String answer;
System.out.println("Pick a number from 1-31\n");
System.out.println("Is your number one of these? 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31");
Scanner a1 = new Scanner(System.in);
answer = a1.next();
if(answer == "yes") {
a = 1;
} else {
a = 0;
}
System.out.println("Is your number one of these? 2, 3, 6, 7, 10, 11, 14, 15, 18, 19, 22, 23, 26, 27, 30, 31");
Scanner a2 = new Scanner(System.in);
answer = a2.next();
if(answer == "yes") {
b = 2;
} else {
b = 0;
}
System.out.println("Is your number one of these? 4, 5, 6, 7, 12, 13, 14, 15, 20, 21, 22, 23, 28, 29, 30, 31");
Scanner a3 = new Scanner(System.in);
answer = a3.next();
if(answer == "yes") {
c = 4;
} else {
c = 0;
}
System.out.println("Is your number one of these? 8, 9, 10, 11, 12, 13, 14, 15, 24, 25, 26, 27, 28, 29, 30, 31");
Scanner a4 = new Scanner(System.in);
answer = a4.next();
if(answer == "yes") {
d = 8;
} else {
d = 0;
}
System.out.println("Is your number one of these? 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31");
Scanner a5 = new Scanner(System.in);
answer = a5.next();
if(answer == "yes") {
e = 16;
} else {
e = 0;
}
number = a + b + c + d + e;
System.out.println("Your number is " + (a + b + c + d + e));
}
}

Answer 1

You made a very common mistake in your code.

Never ever compare java strings with "=="!!!!
this is the comparison for the same reference but not the value of the string!
Use "equals" (eg. "blablabla".equals("blablabla");) this is the correct way of comparing strings.

I used to make this error a lot when i started java so you are not alone ;)

Answer 2

Thanks man