读文本型：

#include <windows.h>
#include <iostream>
using namespace std;
int main()
{
    HKEY hOpen;
    char key[255] = "SOFTWARE\\Microsoft\\Internet Explorer\\URL Compatibility";
    char name[10] = "Version";
    char buf[255];
    DWORD size;
    if(ERROR_SUCCESS==RegOpenKeyEx(HKEY_LOCAL_MACHINE, key, 0, KEY_READ, &hOpen))
    {
        RegQueryValueEx(hOpen, name, NULL, NULL, (BYTE*)buf, &size);
        cout << buf << endl;
    }
    RegCloseKey(hOpen);
    Sleep(3000);
    return 0;
}

读数值型：

#include <windows.h>
#include <iostream>
using namespace std;
int main()
{
    HKEY hOpen;
    char key[255] = "SOFTWARE\\Microsoft\\Internet Explorer\\URL Compatibility";
    char name[10] = "Version";
    DWORD buf = 0;
    DWORD size = sizeof(buf);
    if(ERROR_SUCCESS==RegOpenKeyEx(HKEY_LOCAL_MACHINE, key, 0, KEY_READ, &hOpen))
    {
        RegQueryValueEx(hOpen, name, NULL, NULL, (LPBYTE*)buf, &size);
        cout << buf << endl;
    }
    RegCloseKey(hOpen);
    Sleep(3000);
    return 0;
}