/*  Write a function that returns the longest sequence 
 *  of consecutive zeroes in a binary string.
 */
std::string longestZero(std::string str) {
	std::string count = "";
	std::string biggestCount = count;
// 011000010110001
	// loop through each character in string
	for(int i=0;i<str.size();i++){
		// save each zero in the string to the end of count
		if(str[i] == '0'){
			count.append("0");
		}
		else if(str[i]=='1'){
			count = "";
		}
		// if the string is not a one or zero, this is not a binary string. program ABORTED!
		else {
			assert(false);
		}
		//  compare each count to find the biggestCount
		if(count.size()>biggestCount.size()){
			biggestCount=count;
		}
	}
		// return the biggestCount.
	return biggestCount;
}