Cheat Engine

[ulysse31]

APIs to use :
EnumProcessModules
GetModuleInformation
So, ModuleInfo.lpBaseOfDll is the variable of your code which holds xxx.exe address as you call it, given that the handle you used is the one of the process you are targeting
Applied to your pointer scan this means that
xxx.exe address is ModuleInfo.lpBaseOfDll
to this address you add 0x0198f9b8
so if ModuleInfo.lpBaseOfDll == 0x40000
then the new address is 0x1d8f9b8 (result of 0x400000 + 0x0198f9b8)
this is the address you read ( 0x1d8f9b8)
the value you read, you then add the offset 0x5c8 to it and you read the target process at the corresponding address