CODEWITHSUNDEEP
java
nanospeck
nanospeck

Reputation: 3548

What does step ^= 1 mean in Java?

I know that ^ is the xor operator in Java. But I couldn't understand it in the following context.

int step = 0;
...
step ^=1;

Source: Google Code Jam 2014 (Participant's answer)

File Link : here

Upvotes: 0

Views: 223

Answers (5)

Kick Buttowski
Kick Buttowski

Reputation: 6739

it goes under assignment operator category like

 += -= *= /= %= &= ^= |= <<= >>= >>>=

means

^= bitwise exclusive OR and assignment operator

step ^=1; as same as step = step ^ 1;

Upvotes: 2

Paul Boddington
Paul Boddington

Reputation: 37645

As others have pointed out, step ^=1 flips the least significant bit of step. This makes even numbers get 1 bigger, and odd numbers get 1 smaller.

Examples:

 0 --> 1
 1 --> 0
 7 --> 6
 6 --> 7
-3 --> -4

Upvotes: 1

Afzal Ahmad
Afzal Ahmad

Reputation: 626

From Java Tutorials,

^ Assume integer variable A holds 60 and variable B holds 13 then: Binary XOR Operator copies the bit if it is set in one operand but not both.(A ^ B) will give 49 which is 0011 0001

In your case it is,

step = step^1

and in result you get step=1

http://www.tutorialspoint.com/java/java_basic_operators.htm

Upvotes: 1

SMA
SMA

Reputation: 37023

step ^=1 means step = step xor 1. Similar to step += 1 which gets evaluated to step = step + 1

So ^= is short hand xor operator.

So xor table says:

operand1   operand2    output
   0          0         0
   0          1         1
   1          0         1
   1          1         0

so if my step is 1, then 1 xor 1 would be 0.

Upvotes: 1

Keen Sage
Keen Sage

Reputation: 1949

^ stands for XOR operator.

a ^= b is equivalent to a = a ^ b

Upvotes: 2

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