String to Integer

str_to_int.cpp

#include <iostream>
#include <string>

int main() {
	std::string numberString = "1234";
	int numberInt = 0;
	for (int i = 0; i < numberString.length(); i++) {
    	numberInt = numberInt * 10 + numberString[i] - '0';
    }
    std::cout << "String number: " << numberString << std::endl;
    std::cout << "Integer number: " << numberInt << std::endl;
	return 0;
}