As a Group IV element, carbon has a large redox manifold. #C^(-IV)# to #C^(IV)#. Carbon is slightly more electronegative than hydrogen.
I will try to provide examples for each one.
#C^(-IV):# #CH_4#
#C^(-III):# #H_3C-CH_3#
#C^(-II):# #H_3C^(-III)-C^(-II)H_2-C^(-III)H_3#
#C^(-I):# #(H_3C)_3C^(-I)H#, or #"benzene"#
#C^(0):# #"Soot or bbq charcoal"# or #CH_2X_2#
#C^(I):# #(H_3C)_3C-X#
#C^(+II):# #""^(-)C-=O^+, (H_3C)_2CX_2#
#C^(+III):# #X_3C-CX_3#
#C^(+IV):# #CO_2#, #CX_4#
Note that for the purposes of oxidation state assignment, when we break a #C-C# bond, the electrons are assume to be shared equally, i.e. #C-Crarr2xx*C#. Also note that oxidation states are a FORMALISM, they represent an ad hoc way of counting electrons and not a physical reality.
