string to int c 2b 2b

1#include <iostream>
2#include <string>
3
4int main() {
5
6    std::string str = "123";
7    int num;
8
9    // using stoi() to store the value of str1 to x
10    num = std::stoi(str);
11
12    std::cout << num;
13
14    return 0;
15}

1int thing = std::stoi(string);

1// For C++11 and later versions
2string str1 = "45"; 
3string str2 = "3.14159"; 
4string str3 = "31337 geek"; 
5
6int myint1 = stoi(str1); 
7int myint2 = stoi(str2); 
8int myint3 = stoi(str3); 
9
10// Output
11stoi("45") is 45
12stoi("3.14159") is 3
13stoi("31337 geek") is 31337 

1#include <iostream>
2#include <string>
3using namespace std;
4int main() {
5 
6    string s = "10";
7 
8    try
9    {
10        int i = stoi(s);
11        cout << i << '\n';
12    }
13    catch (invalid_argument const &e)
14    {
15        cout << "Bad input: std::invalid_argument thrown" << '\n';
16    }
17    catch (out_of_range const &e)
18    {
19        cout << "Integer overflow: std::out_of_range thrown" << '\n';
20    }
21 
22    return 0;
23}

1// Both functions work identically though you'll need to use "#include <string>" 
2atoi( str.c_str() );
3stoi( str );

1// stoi example
2#include <iostream>   // std::cout
3#include <string>     // std::string, std::stoi
4
5int main ()
6{
7  std::string str_dec = "2001, A Space Odyssey";
8  std::string str_hex = "40c3";
9  std::string str_bin = "-10010110001";
10  std::string str_auto = "0x7f";
11
12  std::string::size_type sz;   // alias of size_t
13
14  int i_dec = std::stoi (str_dec,&sz);
15  int i_hex = std::stoi (str_hex,nullptr,16);
16  int i_bin = std::stoi (str_bin,nullptr,2);
17  int i_auto = std::stoi (str_auto,nullptr,0);
18
19  std::cout << str_dec << ": " << i_dec << " and [" << str_dec.substr(sz) << "]\n";
20  std::cout << str_hex << ": " << i_hex << '\n';
21  std::cout << str_bin << ": " << i_bin << '\n';
22  std::cout << str_auto << ": " << i_auto << '\n';
23
24  return 0;
25}