Syntax
 
    WM_KEYDOWN // Window message sent to window procedure
 
        WPARAM wParam; // Word Parameter( DWORD )
        LPARAM lParam; // Long Parameter ( long )
 
 
Parameters
 
    wParam // holds the key number - see into Virtual keys for the list
 
    lParam
        Specifies the repeat count, scan code, extended-key flag, context code, previous key-state flag, and transition-state flag, as shown in the following table.
 
        0-15
            Specifies the repeat count for the current message. The value is the number of times the keystroke is autorepeated as a result of the user holding down the key. If the keystroke is held long enough, multiple messages are sent. However, the repeat count is not cumulative.
        16-23
            Specifies the scan code. The value depends on the OEM.
        24
            Specifies whether the key is an extended key, such as the right-hand ALT and CTRL keys that appear on an enhanced 101- or 102-key keyboard. The value is 1 if it is an extended key; otherwise, it is 0.
        25-28
            Reserved; do not use.
        29
            Specifies the context code. The value is always 0 for a WM_KEYDOWN message.
        30
            Specifies the previous key state. The value is 1 if the key is down before the message is sent, or it is zero if the key is up.
        31
            Specifies the transition state. The value is always zero for a WM_KEYDOWN message.

	HWND foregroundWindow = GetForegroundWindow();
	char testChar [2];
	testChar[0] = 'h'; testChar[1] = 'i';
	for(int i = 0; i < strlen(testChar); i++){
		SendMessage(foregroundWindow, WM_CHAR, testChar[i], NULL);
	}