Error message: invalid types 'bool...' (array problem)

Hello everyone.

I'm stuck with an error message that neither I nor any of my computer science peeps can understand. The program I wrote is meant to be a simple decimal to binary converter, but with this message it's more complicated than I thought.

Here's the code:

#include <iostream>
#include <cmath>
using namespace std;

int main()
{
	int num = 0;
	int k = 0;
	int max = 0;
	bool binary[100];
	cout << "Enter a decimal number: " ; 
		cin >> num;
		
	while (pow(2,k) <= num)
		k++;
		
	k--;				// Decrements the power after the highest power of 2 is found.	  
	max = k;
	
	while (k >= 0 && num > 0)
	{
		if (pow(2,k) > num)
			binary[k] = 0;
		else
		{
			binary[k] = 1;
			num -= pow(2,k);
		}
		k--;
	}
	
	while (max >= 0)
	{
		cout << binary[max];
		max++;
	}
	
return 0;
}

The error exactly says:
...\dectobin.cpp:27: error: invalid types 'bool [100][double]' for array subscript
...\dectobin.cpp:30: error: invalid types 'bool [100][double]' for array subscript

If it helps, I'm using Quincy... but only because my lecturer is using Quincy.

Any help is appreciated greatly.

PS, is there any reason why the variable k can't be of type int?

Please don't spam the same topic in multiple forums.

I accidentally double posted, and I'm relatively new to this forum. I couldn't work out how to delete this post...