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stringformat with constexpr if
#include <string>
#include <iostream>
#include <memory>
/**
* Convert all std::strings to const char* using constexpr if (C++17)
*/
template<typename T>
auto convert(T&& t) {
if constexpr (std::is_same<std::remove_cv_t<std::remove_reference_t<T>>, std::string>::value) {
return std::forward<T>(t).c_str();
}
else {
return std::forward<T>(t);
}
}
/**
* printf like formatting for C++ with std::string
* Original source: https://stackoverflow.com/a/26221725/11722
*/
template<typename ... Args>
std::string stringFormatInternal(const std::string& format, Args&& ... args)
{
size_t size = snprintf(nullptr, 0, format.c_str(), std::forward<Args>(args) ...) + 1;
std::unique_ptr<char[]> buf(new char[size]);
snprintf(buf.get(), size, format.c_str(), args ...);
return std::string(buf.get(), buf.get() + size - 1);
}
template<typename ... Args>
std::string stringFormat(std::string fmt, Args&& ... args) {
return stringFormatInternal(fmt, convert(std::forward<Args>(args))...);
}
int main() {
std::string s = "a";
const std::string cs = "b";
const char* cc = "c";
int i = 1;
const int i2 = 2;
using namespace std::literals;
std::cout << stringFormat("%s %s %s %s %s %d %d %d \n", s, cs, cc, "d", "e"s, i, i2, 3);
return 0;
}
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