how to change a string to int C++ code example

Example 1: c++ string to int

atoi( str.c_str() )

Example 2: how to string to integer in c++

#include<string>
string str1 = "45"; 
string str2 = "3.14159"; 
string str3 = "31337 geek";

int myint1 = stoi(str1);
std::cout<<stoi(str1);