Beginner question

[tractorboy]

Hi,
Sorry I'm trying to work through some of the beginner problems which are posted here http://www.cplusplus.com/forum/articles/12974/
I'm doing the "Bracketing search" question and my 'code' is below...the trouble is I don't get a different random number each time...i.e. the answer is the same every time I run the program :(. I'm sure the solution is pretty simple but it's annoying me nonetheless.

Thanks!

  #include "stdafx.h"
#include <iostream>
using namespace std;

int _tmain()
{int a, b;
cout<<"Guess the number!\n";
cin>>b;
a= rand() % 100;
if (b!=a);
{do
{if (b>a)
		{cout<<"Too high! Guess again\n";
cin>>b;}
	else if (b<a)
		{cout<<"Too low! Guess again\n";
cin>>b;}}
while (b!=a);
	
if (b==a)
{cout<<"Congratulations, you are correct!\n";}
}

	return 0;
}

[vlad from moscow]

Include headers <cstdlib> and <ctime> and use

std::srand( ( unsigned int )std::time() );

in the very beginning of the program.

[tractorboy]

I've put in the headers but what about this 2nd line? Where does that go? In the "using namespace.." bit?

And why does it not generate a new random number each time?

[tractorboy]

Ok, I found this
http://www.cplusplus.com/reference/cstdlib/rand/

thanks for your help