No access reading memory

#include <iostream>
#include <Windows.h>
#include <TlHelp32.h>

using namespace std;

int main()
{

	HANDLE openprocess;
	PROCESSENTRY32 pEntry;
	MODULEENTRY32 mEntry;
	
	HANDLE processes  = CreateToolhelp32Snapshot(TH32CS_SNAPALL, NULL);

	
	Process32First(processes, &pEntry);

	while(Process32Next(processes, &pEntry))
	{
		if(strcmp(pEntry.szExeFile, "test.exe")==0)
		{
			break;
		}
	}
	
	HANDLE process = CreateToolhelp32Snapshot(TH32CS_SNAPALL, pEntry.th32ProcessID);

	Module32First(process, &mEntry);

	int a = (int)mEntry.modBaseAddr;
	int s = (int)mEntry.modBaseSize;
	BYTE* b;
	b = new BYTE[s];

	cout<< mEntry.szModule << " " << hex << a << endl;

	while(true)
	{
		bool a = Module32Next(process, &mEntry);
		if(a == false)
		{
			break;
		}
		cout<< mEntry.szModule << " " << hex << (int)mEntry.modBaseAddr << endl;
		
	}
	
	
	openprocess = OpenProcess(PROCESS_VM_READ|PROCESS_VM_OPERATION, 0, pEntry.th32ProcessID);

	DWORD old = 0;
	
	VirtualProtectEx(openprocess,(LPVOID)a, s, PAGE_READWRITE, &old);
	
	
	

	if(!ReadProcessMemory(openprocess, (LPCVOID)a, &b, s, 0))
	{
		cout<< "fail";
	}

	cout<< b[0];
	
	cin.get();

}