Question

int cpu = 0;
int player = 0;

char * getPoints()
{
    using namespace std;
    string str = "You: ";
    str += player;
    str += " CPU: ";
    str += cpu;
    char c [100];
    strcpy(c, str.c_str());
    return c;
}

This code doesn’t compile. Is the code wrong or is there something wrong with my compiler?

I’m using Microsoft Visual Studio with the DarkGDK.

If it is me, can someone improve it?

---

This is the output:

1>------ Build started: Project: Pong, Configuration: Debug Win32 ------
1>Compiling...
1>Main.cpp
1>c:\users\martijn\documents\visual studio 2008\projects\pong\pong\main.cpp(42) : warning C4172: returning address of local variable or temporary
1>Linking...
1>libcpmtd.lib(xdebug.obj) : warning LNK4098: defaultlib 'libcmt.lib' conflicts with use of other libs; use /NODEFAULTLIB:library
1>libcpmtd.lib(xdebug.obj) : error LNK2019: unresolved external symbol __malloc_dbg referenced in function "void * __cdecl operator new(unsigned int,struct std::_DebugHeapTag_t const &,char *,int)" (??2@YAPAXIABU_DebugHeapTag_t@std@@PADH@Z)
1>libcpmtd.lib(xdebug.obj) : error LNK2019: unresolved external symbol __free_dbg referenced in function "void __cdecl operator delete(void *,struct std::_DebugHeapTag_t const &,char *,int)" (??3@YAXPAXABU_DebugHeapTag_t@std@@PADH@Z)
1>libcpmtd.lib(stdthrow.obj) : error LNK2019: unresolved external symbol __CrtDbgReportW referenced in function "void __cdecl std::_Debug_message(wchar_t const *,wchar_t const *,unsigned int)" (?_Debug_message@std@@YAXPB_W0I@Z)
1>Debug\Pong.exe : fatal error LNK1120: 3 unresolved externals
1>Build log was saved at "file://c:\Users\Martijn\Documents\Visual Studio 2008\Projects\Pong\Pong\Debug\BuildLog.htm"
1>Pong - 4 error(s), 2 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Answer 1

The errors seem to be from problems with the compiler. Are you sure you have the project set up correctly?

The warning about returning a local variable is serious. You allocate the c array on the stack in your function. When the function returns, the array will be gone from the stack and the pointer you returned ends up pointing to garbage. Consider returning a string instead, or allocate c on the heap.