The executive department shall consist of a governor, lieutenant governor, secretary of state, state controller, state treasurer, attorney general and superintendent of public instruction, each of whom shall hold his office for four years beginning on the first Monday in January next after his election, commencing with those elected in the year 1946, except as otherwise provided in this Constitution. The officers of the executive department shall, during their terms of office, reside within the state. Their official office shall be located in the county where the seat of government is located, there they shall keep the public records, books and papers. They shall perform such duties as are prescribed by this Constitution and as may be prescribed by law, provided that the state controller shall not perform any post-audit functions.