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

1. std::stoi

std::string str = "10";  
int number = std::stoi(str); 

2. string streams

std::string str = "10";  
int number;  
std::istringstream(str) >> number

3. boost::lexical_cast

#include 
std::string str = "10";  
int number;
    
try 
{
    number = boost::lexical_cast(str);
    std::cout << number << std::endl;
}
catch (boost::bad_lexical_cast const &e) // bad input
{
    std::cout << "error" << std::endl;
}

4. std::atoi

std::string str = "10";
int number = std::atoi(str.c_str()); 

5. sscanf()

 std::string str = "10";
 int number;
 if (sscanf(str .c_str(), "%d", &number) == 1) 
 {
     std::cout << number << '\n';
 } 
 else 
 {
     std::cout << "Bad Input";
 }