Reading and writing with a DLL injection C++ - c++

Question

I've run into a bit of a problem and I'm not sure how to do what I am trying to do.
I am using C++ to inject a DLL into an application and I want to alter an address. The problem is that I'm not quite sure how to target it - let me explain...
I know how to use pointers:
int x;
int *myPointer;
myPointer = &x;
*myPointer = 5;
std::cout << x << endl; // 5
And I know that you can point to pointers:
int x;
int *myPointer;
int **myPointer2;
myPointer = &x;
myPointer2 = &myPointer;
**myPointer = 5;
std::cout << x << endl; // 5
I am trying to make a basic game hack by injecting a DLL into a game, and then setting the ammo to a fixed value on a keypress. The injection is working, the keypress is working, but I get a crash whenever I try and access the memory.
I have used Cheat Engine to get the static address for the variable I want to change, along with 3 offsets.
The address info in Cheat Engine looks like this:
Address: 0288A520 = 19
Type: 4 bytes
0 [0288A520 + 0] -> 0288A520
14 [0288A520 + 14] -> 0288A520
384 [0288A3D0 + 384] -> 02881A30
ac_client.exe+109B74 -> 0288A3D0
The value 19 is the one I want to modify in my DLL.
If I close the game and re-open it, I get the correct values coming through using these pointers, but now my issue is I'm not sure how to implement this in C++. How do I represent this static address in C++?
My main thread currently looks like this...
DWORD WINAPI Main_Thread(LPVOID lpParam)
{
while(1)
{
if(GetAsyncKeyState(VK_HOME)) {
// Output value here???
}
Sleep(100);
}
}
Any help is greatly appreciated.

Answer 1

I've got it working. The things I had been trying before were happening because I had an incorrect base address.
My solution can be seen below.
Defining addresses
#define BASE_ADDR 0x00400000
#define AMMO_ADDR 0x00109B74
#define AMMO_OFS1 0x00000384
#define AMMO_OFS2 0x00000014
Get address function
DWORD getAddress(DWORD baseAddress, DWORD offsets[], int offsetCount)
{
DWORD address; // Where the final address will be stored
address = *(DWORD*)(BASE_ADDR + baseAddress); // Add the base address to the modules base address.
// Loop through each offset
for(int i = 0; i < offsetCount; i++) {
address = *(DWORD*)(address + offsets[i]);
}
return address;
}
Changing the value
DWORD ammoOffsets[] = {AMMO_OFS1, AMMO_OFS2};
DWORD ammoAddress = getAddress(AMMO_ADDR, ammoOffsets, 2);
int* ammoPointer = (int*) ammoAddress;
*ammoPointer = 20;