Convert Binary Array to Char Java

Question

I have this binary array:

int[] bitArray = {
    0,1,0,1,0,1,0,0,0,1,1,0,1,0,0,0,0,1,1,0,0,1,0,1,0,0,1,0,0,0,0,0,0,1,1,1,0,0,1,1,
    0,1,1,1,0,1,0,1,0,1,1,0,1,1,1,0,0,0,1,0,0,0,0,0,0,1,1,0,1,0,0,1,0,1,1,1,0,0,1,1,
    0,0,1,0,0,0,0,0,0,1,1,0,1,0,0,1,0,1,1,0,1,1,1,0,0,0,1,0,0,0,0,0,0,1,1,1,0,1,0,0,
    0,1,1,0,1,0,0,0,0,1,1,0,0,1,0,1,0,0,1,0,0,0,0,0,0,1,1,1,0,0,1,1,0,1,1,0,1,0,1,1,
    0,1,1,1,1,0,0,1,};

It makes the phrase: The sun is in the sky How would you convert the int binary array to a char?

Answer 1

ASCII chars are one byte. One byte is eight bits. Separate the array elements in segments of 8 (0-7), (8-15), ...

Store these segments in another array. Use the following constructor to finish.

public String(byte[] bytes, Charset charset)

Remember to specify utf8 as your charset. This causes the chars to be treated as one-byte ASCII chars.

Answer 2

Loop over every byte (8 bits) of the array, create a string of those bits, and then convert those bits to an integer using Integer.parseInt(x,2) and then cast that to a character and added to the result.

  public static void main (String[] args) throws java.lang.Exception
    {
        int[] bitArray = {0,1,0,1,0,1,0,0,0,1,1,0,1,0,0,0,0,1,1,0,0,1,0,1,0,0,1,0,0,0,0,0,0,1,1,1,0,0,1,1,0,1,1,1,0,1,0,1,0,1,1,0,1,1,1,0,0,0,1,0,0,0,0,0,0,1,1,0,1,0,0,1,0,1,1,1,0,0,1,1,0,0,1,0,0,0,0,0,0,1,1,0,1,0,0,1,0,1,1,0,1,1,1,0,0,0,1,0,0,0,0,0,0,1,1,1,0,1,0,0,0,1,1,0,1,0,0,0,0,1,1,0,0,1,0,1,0,0,1,0,0,0,0,0,0,1,1,1,0,0,1,1,0,1,1,0,1,0,1,1,0,1,1,1,1,0,0,1,};

         int CHAR_SIZE = 8;

         String T = "";
         String result ="";
         for (int i=0; i<bitArray.length; i+= CHAR_SIZE)
            {
                for (int j=0; j<CHAR_SIZE; j++)
                    T += Integer.toString(bitArray[i+j]);

                result += Character.toString((char)Integer.parseInt(T, 2));
                T="";
            }

            System.out.println(result);

    }

output

The sun is in the sky

Answer 3

Every eight bits make up a char. You could just loop over the bits and accumulate every eight together:

int[] bitArray = {0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1,};
char[] chars = new char[bitArray.length / 8];
for (int i = 0; i < chars.length; ++i) {
    int c = 0;
    for (int j = i * 8; j < (i + 1) * 8; ++j) {
        c = c << 1;
        c += bitArray[j];
    }
    chars[i] = (char)c;
}

String s = new String(chars);
System.out.println(s);