# Position of rightmost set bit

Write a one line C function to return position of first 1 from right to left, in binary representation of an Integer.

```I/P    18,   Binary Representation 010010
O/P   2
I/P    19,   Binary Representation 010011
O/P   1
```

## Recommended: Please solve it on “PRACTICE ” first, before moving on to the solution.

```Algorithm: (Example 18(010010))
Let I/P be 12 (1100)

1. Take two's complement of the given no as all bits are reverted
except the first '1' from right to left (10111)

2  Do an bit-wise & with original no, this will return no with the
required one only (00010)

3  Take the log2 of the no, you will get position -1 (1)

```

Program:

## C

```#include<stdio.h>
#include<math.h>

unsigned int getFirstSetBitPos(int n)
{
return log2(n&-n)+1;
}

int main()
{
int n = 12;
printf("%u", getFirstSetBitPos(n));
getchar();
return 0;
}
```

## Java

```// Java Code for Position of rightmost set bit
class GFG {

public static int getFirstSetBitPos(int n)
{
return (int)((Math.log10(n & -n)) / Math.log10(2)) + 1;
}

// Drive code
public static void main(String[] args)
{
int n = 12;
System.out.println(getFirstSetBitPos(n));

}
}
// This code is contributed by Arnav Kr. Mandal
```

Output:

`3`

# GATE CS Corner    Company Wise Coding Practice

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