Java - Convert boolean[] to decimal

Question

Hey,

A boolean array can be considered to be a binary number e.g.

boolean[] four = {true, false, false}; //100

I would like to convert such an array to its decimal equivalent e.g.

int decimal = convertBooleanArrayToDecimal(four);
//decimal == 4

How can I do so?

Cheers,

Pete

Answer 1

Try something like this.

long result = 0;
for (boolean bit : four) {
    result = result * 2 + (bit ? 1 : 0);
}

Answer 2

An alternate solution:

long result = 0;
for (boolean bit: boolArray)
{
    result <<= 1;
    if (bit) result += 1;
}

This is mathematically equivalent to Nikita's solution, but I find the bit-shifting version to be clearer.