Hamming distance

Hamming distance
https://en.wikipedia.org/wiki/Hamming_distance
the Hamming distance between two strings of equal length is the number of positions at which the corresponding symbols are different. In another way, it measures the minimum number of substitutions required to change one string into the other, or the minimum number of errors that could have transformed one string into the other.
Hamming distance between two strings of equal length is equal to the total number of positions at which corresponding characters in the two strings are different.

int hammingDistance(char* str1, char* str2)

{

    // If any of the string is null

    // or they are not of the same size, then Hamming distance cannot be calculated.

    if(str1 == NULL || str2 == NULL || strlen(str1) != strlen(str2))

        return -1;

 

    int len = strlen(str1);

    int hDistance = 0;

 

    for(int i=0; i<len; i++)

        if(str1[i] != str2[i])

            hDistance++;

 

    return hDistance;

}

Hamming distance between two integers

int hamming_distance(unsigned x, unsigned y)
{
    int       dist;
    unsigned  val;
    dist = 0;
    val = x ^ y;    // XOR
    // Count the number of bits set
    while (val != 0)
    {
        // A bit is set, so increment the count and clear the bit
        dist++;
        val &= val - 1;
    }
    // Return the number of differing bits
    return dist;
}

http://www.fgdsb.com/2015/01/03/hamming-distance/

int hamming(int a , int b) {

    int res = 0, i, j;

    while (a >0 || b > 0) {

        i = a % 10, j = b % 10;

        if (a == 0 || b == 0 || i != j)

            res++;

        a /= 10, b /= 10;

    }

    return res;

}

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