C++如何将字符串中的字符显示为数字

#include <cstdlib>
#include <iostream>

int main() {
    const char* str = "12345";
    int num = atoi(str);
    std::cout << "Converted number: " << num << std::endl;
    return 0;
}

#include <iostream>
#include <sstream>

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