C++ ::  SendInput - Cursor Position Wrong

I recently wanted to create a (yet) simple program that simulates a mouse movement.So far I managed to make the program work. It does move the mouse, click when expected but the problem is the location it does click at.Here's my code:

#include <Windows.h>
#include <stdio.h>
int leftclick (DWORD x, DWORD y);
int main(){

[code]......

The problem now is: I want the program (for testing purposes) to click at (1920, 1080) and (100, 100) afterwards. Now it does click within a specific range. When I use GetCursorPos to retreive the cursors position it differs quite a bit from where I expected the click to be.

a second question I have is: When I declare the following flag (in the code above) the program does use relative coordinates even though it shouldn't.

input.mi.dwFlags = MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_LEFTDOWN | MOUSEEVENTF_LEFTUP;

Where as it works out well when I add a MOUSEEVENTF_MOVE to it.I couldn't find any solution to this in Microsoft MSDN or any other website.