Get the executable path through the process PID (queryfullprocessimagename)

You need to use the following API

BOOL WINAPI QueryFullProcessImageName(
  __in     HANDLE hProcess,
  __in     DWORD dwFlags,
  __out    LPTSTR lpExeName,
  __inout  PDWORD lpdwSize
);

32 Bit program calls this API Also available 64 Executable path of bit process .

The following is Microsoft's description in the document , Because of the API It's easy to stop repeating

hProcess [in]

A handle to the process. This handle must be created with the PROCESS_QUERY_INFORMATION or PROCESS_QUERY_LIMITED_INFORMATION access right. For more information, see Process Security and Access Rights 
.

dwFlags [in]

This parameter can be one of the following values.

Value	Meaning
0	The name should use the Win32 path format.
PROCESS_NAME_NATIVE 0x00000001	The name should use the native system path format.