Variadic templates example: simple logger

cpp-variadic-d.cpp

#include <chrono>
#include <cstring>
#include <iostream>
#include <string>

using namespace std;
using std::chrono::system_clock;

template <typename... Args>
void log(const char* format, Args... args) {
  string formatAsString = "[%s] ";
  formatAsString += format;
  formatAsString += "\n";
  const time_t currentTime = system_clock::to_time_t(system_clock::now());
  printf(formatAsString.c_str(), strtok(ctime(&currentTime), "\n"), args...);
}

int main() {
  log("Example 4: Simple logger");
  log("Test message %d", 1);
  log("Multiple elements %d, %.3f", 10, 152.39798);
  log("IO Error: Could not load file %s", "hello_variadic.txt");
  return 0; 
}