Mainly because South Africa is arepublic meaning that elections are held to elect a head of state in South Africa , we find that the president held both the positions of the head of state and head of government, in that the South African president has both the functions of the head of state and head of government, but the main functions of the president is that to veto legislation and perform some of the ceremonial functions, but in this instance the ddeputy can assist the president, lets say the president has visited foreign countries maybe to attend funeral of another state , the deputy can act in the position of the president