stoi未在此範圍內聲明？

Question

我正在嘗試使用stoi()將string轉換爲int，但我得到的錯誤代碼爲error: ‘stoi’ was not declared in this scope。這是給定的代碼。

#include <iostream> 
#include <string> 

int main() 
{ 
    std::string str1 = "45"; 
    std::string str2 = "3.14159"; 
    std::string str3 = "31337 with words"; 
    std::string str4 = "words and 2"; 

    int myint1 = std::stoi(str1); 
    int myint2 = std::stoi(str2); 
    int myint3 = std::stoi(str3); 
    // error: 'std::invalid_argument' 
    // int myint4 = std::stoi(str4); 

    std::cout << "std::stoi(\"" << str1 << "\") is " << myint1 << '\n'; 
    std::cout << "std::stoi(\"" << str2 << "\") is " << myint2 << '\n'; 
    std::cout << "std::stoi(\"" << str3 << "\") is " << myint3 << '\n'; 
    //std::cout << "std::stoi(\"" << str4 << "\") is " << myint4 << '\n'; 
} 

Answer 1

stoi是從C++ 11，你應該嘗試與atoi