Fast algorithms and data structures of power

Calculating a power of a fast power b

 int quickPower(int a, int b)
{  
    int ans = 1, base = a;
    while(b)
    {
        if(b & 1) ans *= base;//b&1表示b为偶数时，b&1为0，反之为1；
        base *= base;
        b >>= 1;
    } 
    return ans;
}