How convert string to number?

Question

i want look, easy example function!
string a = "123";
.....
int b = a;

Answer 1

use the default library/function in C++
#include <string>
Readup/Google about it, there are quite a couple of functions in that. One of it has what you want.

Answer 2

#include <iostream>
#include <stdlib.h>
using namespace std;

int main() {
string a = "1234";
int b = atoi(a.c_str());
++b;
cout<<b<<endl;
return 0;
}

Answer 3

in python:
b=int (a)

for C++ check function to convert
stoi () function is there

Answer 4

int a = int(stringInAnIntegerFormat);