In C++ there are no methods/functions to convert std string to integer. But, by using C standard library (cstdlib or stdlib.h) we can convert char* (C string) to integer using atoi function. We can also convert string to char* (C string) using c_str function in string class. Thus, we can convert string to integer via char*. This is the function (I call as stoi) and the example:
#include <iostream>
#include <cstdlib>
using namespace std;
int stoi(string _str) {
return atoi(_str.c_str());
}
int main() {
string current_year = "2009";
string birth_year = "1987";
int age = stoi(current_year) - stoi(birth_year);
cout << "Age = " << age << " years old" << endl;
return 0;
}
Output:
Age = 22 years old
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