Keyboard simulation fail

Question

I am making a program and i need it to type a random letter from an array. This is how i tried to do it:

{
srand ( time(NULL) );
WORD arrayNum[4] = {0x41, 0x42, 0x43, 0x44};
int RandIndex = rand() % 4;

INPUT ip;
ip.type = INPUT_KEYBOARD;
ip.ki.wScan = 0;
ip.ki.time = 0;
ip.ki.dwExtraInfo = 0;
ip.ki.wVk = arrayNum; 
ip.ki.dwFlags = 0; 
SendInput(1, &ip, sizeof(INPUT));
ip.ki.dwFlags = KEYEVENTF_KEYUP; 
SendInput(1, &ip, sizeof(INPUT));
}

I must say i am new with this and i don't really know what should i do. The error i get says:

invalid conversion from 'WORD* {aka short unsigned int*}' to 'WORD {aka short unsigned int}' [-fpermissive]

This confuses me a lot..

Answer 1

I think the issue here is in this line:

ip.ki.wVk = arrayNum;

Here, the wVk field is supposed to be a WORD representing the virtual key code to send . However, you've assigned it arrayNum , which is an array of WORD s. Based on your code, I think you meant

ip.ki.wVk = arrayNum[RandIndex];

since you weren't using RandIndex anywhere. Going forward, I'd recommend compiling with the warning level turned all the way up, since it probably would have flagged the non-use of RandIndex in the code.

(Also, if you do ask more questions on Stack Overflow, please try to include more information about the error message. I had to look up the docs to determine which line that particular error occurred on. It's a lot easier for people to help out if they can see the specific line where things went wrong.)

Answer 2

You are passing the actual array itself to wVk when you should be passing a specific element of the array instead:

ip.ki.wVk = arrayNum[RandIndex]; 

That being said, I would suggest using the KEYEVENTF_UNICODE flag when sending text characters with SendInput() , don't use virtual key codes. And you should pass 2 INPUT structures in one call to SendInput() , like @IInspectable suggested. Don't call SendInput() twice for each INPUT , that defeats some of the benefits of using SendInput() :

srand ( time(NULL) );
LPCWSTR chars = L"ABCD";
int RandIndex = rand() % 4;

INPUT ip[2];
memset(ip, 0, sizeof(ip));

ip[0].type = INPUT_KEYBOARD;
ip[0].ki.wScan = (WORD) chars[RandIndex]; 
ip[0].ki.dwFlags = KEYEVENTF_UNICODE;

memcpy(&ip[1], &ip[0], sizeof(INPUT));
ip[1].ki.dwFlags |= KEYEVENTF_KEYUP; 

SendInput(2, ip, sizeof(INPUT));