Given a real number between 0 and 1 (e.g., 0.72) that is passed in as a double, print the binary representation. If the number cannot be represented accurately in binary with at most 32 characters, print "ERROR."

CareerCup5.2.cpp

#include <iostream>
#include <string>

std::string PrintBinary(float);
int main()
{
  std::cout<<PrintBinary(0.81256)<<std::endl;
}

std::string PrintBinary(float num)
{
	if(num>=1||num<0)
	{
		return "ERROR";
	}
	if(num==0)
	{
		return 0;
	}
	
	std::string result = "0.";
	int count=0;
	while(num!=0)
	{
		count++;
		num=num*2;
		if(num>=1)
		{
			result=result+"1";
			num-=1;
		}
		else
		{
			result=result+"0";
		}
		if(count>32)
		{
			return "ERROR";
		}
	}
	return result;
}

this will always go to the ERROR

Your code is fine. However, it always returns Error. Based on my checking, in the editor which I am using (.Net 2012) the value which is assigned to num is slightly different from the one that I have set. For example, I have set num to 0.4 but its real value is 0.400000006 which cause the program to return ERROR.
you can see the exact value of the num by printing it with a high precision using this command:
cout << setprecision(10) << d; // #include