Freaking Math <simplified> by I.K

#include <iostream>
#include <time.h>
#include <cstdlib>
#include <conio.h>
using namespace std;

int a, b, c;
char equ_mark;

void Intro ()
{
printf ("---WELCOME TO MATH GAME---\n\n");
printf ("* How to play: \n");
printf ("Press y if the calculation is right, n if wrong. You have 2 seconds.\n\n");
printf ("press any key to start....");
}

void RandomQ ()
{
srand (time(NULL));
a = rand() % 16;
b = rand() % 16;
c = rand() % 31;
int x = rand() % 1;
if (x == 0) equ_mark = ' ';
else equ_mark = '-';
}

int main ()
{
int point = 0;
bool lose = false;

Intro();

fflush (stdin);
getch();

while (lose != true)
{
double gap;

RandomQ();
// display the q
printf (a, ' ', equ_mark, ' ', b, " = ", c);

time_t start, end;
// time counter
time (&start);
if (kbhit())
{
time (&end);
char key = tolower (getch());
gap = difftime (end, start);
}

// result check
if (gap <= 2.0)
{
if (equ_mark == ' ')
{
if (((a b == c) && (key == 'y')) || ((a b != c) && (key == 'n'))) // phong doan dieu kien nay co van de , chua nghien cuu ki nhung doan se co van de
//re: bac nghien cuu r hang ket luan dum tui
{
cout << "Right! Time elapsed: " << gap << "seconds" << endl;
point  ;
}
else
{
printf ("Oops, wrong...you lose.");
lose = true;
}
}

if (equ_mark == '-')
{
if (((a-b == c) && (key == 'y')) || ((a-b != c) && (key == 'n'))) //chua tim hieu bai toan nhung doan la co van de
//re: hay the, chua tim hieu ma bac da noi nhu 1 vi than
{
cout << "Right! Time elapsed: " << gap << "seconds" << endl;
point  ;
}
else
{
printf ("Oops, wrong...you lose.");
lose = true;
}
}
}

else
{
cout << "Time elapsed: " << gap << "seconds" << endl;
printf ("Too slow. You lose");
lose = true;
}

getch();
system("cls");
}

printf ("Your point: ", point);
system("pause");
}