If you're using C++ ranges - the full ranges-v3 library, not the limited functionality accepted into C++20 - you could do it this way:

auto results = str | ranges::views::tokenize(" ",1);

... and this is lazily-evaluated, i.e. O(1) time and space. You can alternatively set a vector to this range:

auto results = str | ranges::views::tokenize(" ",1) | ranges::to<std::vector>();

this will take O(m) space and O(n) time if str has n characters making up m words.

See also the library's own tokenization example, here.

If you're using C++ ranges - the full ranges-v3 library, not the limited functionality accepted into C++20 - you could do it this way:

auto results = str | ranges::views::tokenize(" ",1);

... and this is lazily-evaluated. You can alternatively set a vector to this range:

auto results = str | ranges::views::tokenize(" ",1) | ranges::to<std::vector>();

this will take O(m) space and O(n) time if str has n characters making up m words.

See also the library's own tokenization example, here.

If you're using C++ ranges - the full ranges-v3 library, not the limited functionality accepted into C++20 - you could do it this way:

auto results = str | ranges::views::tokenize(" ",1);

... and this is lazily-evaluated, i.e. O(1) time and space. You can alternatively set a vector to this range:

auto results = str | ranges::views::tokenize(" ",1) | to<std::vector>();

this will take O(m) space and O(n) time if str has n characters making up m words.

See also the library's own tokenization example, here.

If you're using C++ ranges - the full ranges-v3 library, not the limited functionality accepted into C++20 - you could do it this way:

auto results = str | ranges::views::tokenize(" ",1);

... and this is lazily-evaluated, i.e. O(1) time and space. You can alternatively set a vector to this range:

auto results = str | ranges::views::tokenize(" ",1) | ranges::to<std::vector>();

this will take O(m) space and O(n) time if str has n characters making up m words.

See also the library's own tokenization example, here.