Find XOR of all numbers in a given range

Question

You are given a large range [a,b] where \'a\' and \'b\' can be typically between 1 and 4,000,000,000 inclusive. You have to find out the XOR of all the numbers in the given

Answer 1

To support XOR from 0 to N the code given needed to be modified as below,

int f(int a) {
    int []res = {a, 1, a+1, 0};
    return res[a % 4];
}

int getXor(int a, int b) {
    return f(b) ^ f(a);
}