DLLs?

Alright so I'm new to DLLs. I'm trying to make a DLL to inject/attach to a game emulator, and here's my code

Code:

#include <windows.h>
#include <cstdio>
#include <cstdlib>

void cheats();

BOOL APIENTRY DllMain (HINSTANCE hInst     /* Library instance handle. */ ,
                       DWORD reason        /* Reason this function is being called. */ ,
                       LPVOID reserved     /* Not used. */ )
{
    switch (reason)
    {
      case DLL_PROCESS_ATTACH:
           cheats();
        break;

      case DLL_PROCESS_DETACH:
           cheats();
        break;

      case DLL_THREAD_ATTACH:
           cheats();
        break;

      case DLL_THREAD_DETACH:
           cheats();
        break;
    }
           cheats();

    /* Returns TRUE on success, FALSE on failure */
    return TRUE;
}

void cheats()
{
    // the base address is dynamic.. this gets it from the base pointer
    int dynamic_base_address = *((int*)0x0059EC80);
    // get the hp using the base address and the offset
    int* hp = (int*)(dynamic_base_address+0x98);
    // set hp & max hp to 257
    *hp = 0x01010101;
}
// just in case it calls int main
int main(){
           cheats();}

but whether I inject the DLL with an injector, attach it to the process with the compiler, or just run debug with the program set as a host program, nothing happens. Even when I made cheats()

Code:

void cheats() { system("C:\windows\system32\mshearts.exe"); }

nothing happened. I'm using DevC++ (downloading teamSuite).