Function to generate binary representation of arbitrary numeric type. Fast. Not thread-safe.

binary.cc

#include <iostream>

template<typename T> char* binary(T n) {
	const int bits = sizeof(T)*8;
	static char str[bits+1];
	str[bits] = 0;
	for(int i = 0; i < bits; i++) {
		str[bits-i-1] = '0' + (n & 1);
		n = n >> 1;
	}

	return str;
}

int main() {
	char c = 1 << (8*sizeof(char)-1);
	std::cout << binary(c) << std::endl;
	c = ((unsigned char)c) >> 1;
	std::cout << binary(c) << std::endl;
	return 0;
}