How can I find the value of what a memory address currently holds?

Question

How do you read the address of a program and return the value of what ever the data the address holds? I have the following code which reads an offset address of a program, but I would like to return the value of the address that I'm checking to do some other stuff with it.

inline Mem *Read(DWORD64 address)
{
    this->value = address;
    return (this->r(0));
}

inline Mem *r(DWORD64 ofs)
{
    if (!this || !value)
        return 0;

    if (!ReadProcessMemory(Handle, (void*)(value + ofs), &value, sizeof(DWORD64), 0))
        return 0;

    return this;
}



m.Read(0x1428003C0)->r(0x100);

For example, so I read the offset 0x100 inside the address 0x1428003C0, I know it holds the value of vehicle speed how can I return the speed value from that address? I would like to find out the speed and depends on the speed I would apply breaks or accelerate. I have tried to cout the m.read command, and I get weird garbage that I do not understand. I'm guessing it's the static memory address of the program that I'm currently reading?

Answer 1

On successful return value should contain the content of the memory. You need to check the documentation to determine what format that is.

However, as a first guess I would try:

Mem m;
if (m.Read(0x1428003C0)->r(0x100) )
{
    double* val = (double*)(&m.value);
    if (val != nullptr)
    std::cout << *val << std::endl;
}

Answer 2

If you know you have a valid address you can simply cast it to the right pointer type to read the memory. Note that this is dangerous if you don't have a valid address the result is undefined behavior, and you could just be reading garbage.