printb.cpp

#include <algorithm>
#include <cstring>
#include <iostream>
#include <iomanip>

void printb(const char* title, const unsigned char *buffer, size_t length) {
	int indent = (strlen(title) > 6 ? ((strlen(title) + 2) / 6 + 1) * 6 : 7 + 2);
	std::cout << title << ":" << std::string(indent - strlen(title) - 2, ' ');
	for(size_t i = 0; i < length; i++) {
		std::cout << ((i != 0 && i % 16 == 0) ? "\n" + std::string(indent, ' ') : " ");
		std::cout << std::setfill('0') << std::hex << std::setw(2) << (int)buffer[i] << std::dec;
	}
	std::cout << '\n';
}

int main(void) {
	const int BUFFER_SIZE = 40;
	uint8_t* buffer = (uint8_t*) calloc(BUFFER_SIZE, sizeof(uint8_t));

	printb("buffer", buffer, 40);
	std::generate_n(buffer, BUFFER_SIZE, std::rand);    
	printb("random_buffer", buffer, 40);
}

/* outputs:
buffer:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
         00 00 00 00 00 00 00 00
random_buffer:    67 c6 69 73 51 ff 4a ec 29 cd ba ab f2 fb e3 46
                  7c c2 54 f8 1b e8 e7 8d 76 5a 2e 63 33 9f c9 9a
                  66 32 0d b7 31 58 a3 5a
*/