1. A method for modifying a computer program, the method comprising the steps of: a computer receiving a header file defining a number of values associated with a number of virtual functions; the computer utilizing the header file to receive an instruction string formatted for interactions with the number of virtual functions of the computer program during execution of the computer program, the instruction string comprising a command line switch, a new value for a virtual function, and instructions to replace a current value in the virtual function with the new value while the computer program is executing, wherein the number of virtual functions have replaced a number of original code segments in the computer program and are configured to receive new values for current values from the instruction string, the instruction string having new function data therein for replacing current function data of a virtual function of the computer program during execution of the computer program by a processor unit, wherein the virtual function is capable of being changed during execution of the computer program to modify behavior of the computer program; and the computer replacing the current function data in the virtual function with the new function data, wherein the new function data modifies the computer program, and wherein a behavior of the computer program is modified by an interaction between the virtual function and the instruction string while the computer program is executed by the processor unit.