int hitDaEnterKey()
{
    INPUT ip;
    // Set up a generic keyboard event.
    ip.type = INPUT_KEYBOARD;
    ip.ki.wScan = 0; // hardware scan code for key
    ip.ki.time = 0;
    ip.ki.dwExtraInfo = 0;
    // Press and release Enter Key
    ip.ki.wVk = 0x0D;
    ip.ki.dwFlags = 0;
    SendInput(1, &ip, sizeof(INPUT));
    // release
    ip.ki.dwFlags = KEYEVENTF_KEYUP;
    SendInput(1, &ip, sizeof(INPUT)); 
    return 0;
}
OR
    int hitDaEnterKey(INPUT *ip)
    {        
        // Press and release Enter Key
        ip->ki.wVk = 0x0D;
        ip->ki.dwFlags = 0;
        SendInput(1, ip, sizeof(INPUT));
        // release
        ip->ki.dwFlags = KEYEVENTF_KEYUP;
        SendInput(1, ip, sizeof(INPUT)); 
        return 0;
    }
int main()
{
    // This structure will be used to create the keyboard
    // input event.
    INPUT ip;
    Sleep(2500);
    // Set up a generic keyboard event.
    ip.type = INPUT_KEYBOARD;
    ip.ki.wScan = 0; // hardware scan code for key
    ip.ki.time = 0;
    ip.ki.dwExtraInfo = 0; 
    // Press the "A" key
    ip.ki.wVk = 0x41; // virtual-key code for the "a" key
    ip.ki.dwFlags = 0; // 0 for key press
    SendInput(1, &ip, sizeof(INPUT));
    // Release the "A" key
    ip.ki.dwFlags = KEYEVENTF_KEYUP; // KEYEVENTF_KEYUP for key release
    SendInput(1, &ip, sizeof(INPUT)); 
    hitDaEnterKey(&ip);
    return 0;
}
solved Why iisn’t my function working when it’s called? [closed]