How can I convert a std::string to int?

Question

Just have a quick question. I\'ve looked around the internet quite a bit and I\'ve found a few solutions but none of them have worked yet. Looking at converting a string to

Answer 1

To be more exhaustive (and as it has been requested in comments), I add the solution given by C++17 using std::from_chars.

std::string str = "10";
int number;
std::from_chars(str.data(), str.data()+str.size(), result);

If you want to check whether the conversion was successful:

std::string str = "10";
int number;
auto [ptr, ec] = std::from_chars(str.data(), str.data()+str.size(), result);
assert(ec == std::errc{});
// ptr points to chars after read number

Moreover, to compare the performance of all these solutions, see the following quick-bench link: https://quick-bench.com/q/GBzK53Gc-YSWpEA9XskSZLU963Y

(std::from_chars is the fastest and std::istringstream is the slowest)