Update C++ Code originally written in 2003

I have a C++ code written in 2003 but If I try to compile it in an actual machine with current version of SO and g++, I have to many warnings and errors because some functions was changed or deprecated. Also, complie it and run the resultant file, I have that error: "Segmentation fault (core dumped)" This C++ code have to manny errors, but almost all errors are the same (deprecated conversion from string constant to 'char*').