void* INPUT();
...
function main()
{
  ...  

  //  GetProcAddress(WinUser.h, INPUT); // compiler gives error
  GetModuleHandle(INPUT); // works?
  INPUT ip; // compiler gives error here
 ...
}

int __stdcall MessageBox(int hWnd, char *lpText, char *lpCaption, int uType);
MessageBox = GetProcAddress(LoadLibrary("User32.dll"), "MessageBoxA");

MessageBox(0, "cool", "A messagebox", 0);

#include <acknex.h>
#include <windows.h>
#include <stdio.h> 
#include <default.c>

#define _INPUT_MOUSE 		0
#define _INPUT_KEYBOARD 	1
#define _INPUT_HARDWARE 	2

typedef struct { 
	int type;
	int wVk;
	int wScan;
	int dwFlags;
	int time;
	long dwExtraInfo;
} 	INPUT_STRUCT;

INPUT_STRUCT input;

function main()
{
      ...

        //set up SENDINPUT function
	int __stdcall SENDINPUT(int nInputs, int* pInputs, int cbSize);
	SENDINPUT = GetProcAddress(LoadLibrary("User32.dll"), "SendInputU");
	
        //set up input
	input.type = _INPUT_KEYBOARD;
	input.wScan = 0; // hardware scan code for key
	input.time = 0;
	input.dwExtraInfo = 0;
	
	wait(-3); //time to switch to notepad
	//Press A
	input.wVk = 0x41; // virtual-key code for the "a" key
	input.dwFlags = 0; // 0 for key press
	SENDINPUT(1, &input, sizeof(INPUT_STRUCT));
	
	// Release A
	input.dwFlags = 0x0002; // KEYEVENTF_KEYUP for key release
	SENDINPUT(1, &input, sizeof(INPUT_STRUCT));
}