The general purposes of this Criminal Code are:
(1) To proscribe conduct which unjustifiably and inexcusably causes or threatens harm to individual or public interests;
(2) To give fair warning of the nature of the conduct proscribed and of the sentences authorized upon conviction;
(3) To define the act or omission and the accompanying mental state which constitute each offense;
(4) To differentiate upon reasonable grounds between serious and minor offenses and to prescribe proportionate penalties therefor; and
(5) To insure the public safety by preventing the commission of offenses through the deterrent influence of the sentences authorized, the rehabilitation of those convicted and their confinement when required in the interests of public protection.