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javabitbitmask
Simon Jensen
Simon Jensen

Reputation: 486

Java Integer index to bit position

I'm trying to make a dynamic method to check a number through binary anding. I've tried a variety of different approaches but just can't wrap my head around it.

what I need is a method that converts an integer index position and returns a boolean.

private boolean bitwiseAnding(int val, int indx){
    //TODO Convert indx to a bitmask here
    return (val & bitmask)==1;
}

for example:

1 = 0x01
2 = 0x02
3 = 0x04
4 = 0x08
and so on

Upvotes: 1

Views: 1298

Answers (2)

Krzysztof Atłasik
Krzysztof Atłasik

Reputation: 22595

You have to use bit shifting operator:

private boolean bitwiseAnding(int val, int indx){
    int mask = 1 << (indx-1);
    return (val & mask) != 0;
}

Upvotes: 5

Andy Turner
Andy Turner

Reputation: 140319

Just use bit shifting:

int bitmask = 1 << (indx-1);

But note that you'll only get true for ==1 if indx == 1. You might mean:

(val & bitmask) != 0

Upvotes: 5

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