find_first_one
count_trailing_ones
count_leading_ones
find_first_zero
count_trailing_zeros
count_leading_zeros

See Find First Set.

The first 1 bit is often of interest.

This becomes more interesting if the number is signed, in which case, we may be looking for the arithmetic first and last 1 bits.

Implement these functions.

std::size_t first_one( unsigned int value );
std::size_t  last_one( unsigned int value );

std::size_t first_one( int value );
std::size_t  last_one( int value );

std::size_t arithmetic_first_one( int value );
std::size_t  arithmetic_last_one( int value );

Templated

For a templated data type, you will have to recall that the size of the type can be found using the sizeof operator.

template <typename T>
std::size_t first_one( T value );

template <typename T>
std::size_t  last_one( T value );

template <typename T>
std::size_t arithmetic_first_one( T value );

template <typename T>
std::size_t  arithmetic_last_one( T value );

If the type is unsigned, the arithmetic variants are identical to the descriptions given above.

To tell whether or not the type is signed, you can access the member variable std::is_signed<T>::value of the structure defined in the type_traits library.