在C++中将字符串转换为数字

#include <iostream>
#include <string>

int main() {
    std::string str = "12345";
    int num = std::stoi(str);
    std::cout << "Converted number: " << num << std::endl;
    return 0;
}

#include <iostream>
#include <string>
#include <sstream>

int main() {
    std::string str = "12345";
    std::stringstream ss(str);
    int num;
    ss >> num;
    std::cout << "Converted number: " << num << std::endl;
    return 0;
}

#include <iostream>
#include <string>

int main() {
    std::string str = "12345";
    int num;
    auto result = std::from_chars(str.data(), str.data() + str.size(), num);
    if (result.ec == std::errc()) {
        std::cout << "Converted number: " << num << std::endl;
    } else {
        std::cout << "Conversion failed." << std::endl;
    }
    return 0;
}