Can anyone help me?

I have received several source codes (I think my friend use Turbo C++ (DOS version) to write, because there is an extension prj after each of the files) and call me to use Microsoft Visual C++ 5 and Codebase 4 to compile the codes. Someone advise me to changed the codes to the extension .cpp. And actually I have changed them. But another things happened when I compiled the codes again. Some of the results listed at the end of this mail. My friend told the codes can compile in its computer. I think the problem is Microsoft Visual C++ cannot support C programming practise, am I right? How can I do? Wayne (Encl.) timer.obj warning C4007: 'main' : must be '__cdecl' timer.obj error C2664: 'open' : cannot convert parameter 1 from 'class Code4 *' to 'class Code4 &' timer.obj error C2039: 'tag_select' : is not a member of 'Data4' timer.obj error C2039: 'tag' : is not a member of 'Data4' timer.obj error C2664: 'open' : cannot convert parameter 1 from 'class Code4 *' to 'class Code4 &' timer.obj error C2039: 'tag_select' : is not a member of 'Data4' timer.obj error C2039: 'tag' : is not a member of 'Data4' timer.obj error C2039: 'assign_long' : is not a member of 'Field4' Error executing cl.exe. timer.obj - 7 error(s), 1 warning(s)