You do receive the value for c just fine.
Say, your input is: "123 4.567 some more text here". In this case, a will be 123, b will be 4.567 and c will be (not 's', but) ' ' i.e. a space, which follows the value put into b.
If your input would be "123 4.56some more text", in that case, c will be 's'.