using System;
class FirstSetBit
{
// Function to find the position of the first set bit
static int FindFirstSetBitPosition(int num) {
// Edge case: If the number is 0, there are no set bits
if (num == 0) {
return 0; // Return 0 to indicate no set bit
}
/*
* num & -num isolates the lowest set bit.
* Math.Log(...) / Math.Log(2) gives the zero-based index of that bit.
*/
return (int)(Math.Log(num & -num) / Math.Log(2));
}
static void Main()
{
int num = 4224; // Binary: 0001 0000 1000 0000
// Find and display the position of the first set bit
int position = FindFirstSetBitPosition(num);
if (position == 0) {
Console.WriteLine("The number has no set bits (it's 0).");
}
else {
Console.WriteLine("The position of the first set bit is: " + position);
}
}
}
/*
run:
The position of the first set bit is: 7
*/
