Have a string as an integer

Question

#include <iostream>
using namespace std;
int main ()
{
    string a;
    cin >> a;
    int b=10;
    cout << a+b;
    return 0;
}

I have a problem with the code above. I know it's wrong, but it shows my point.

I'm wondering if I get a number as a string, how can I have it as an integer? For example, I give 12 to the program after running. So a will be "12". Now I want the summation of 12 and the variable b. What should I do? How can I extract 12 as an integer from my string?

Is `a` required to be a `string`? Can you just change it to `int`? — Cornstalks, Feb 20 '15 at 17:04
http://stackoverflow.com/questions/7663709/convert-string-to-int-c — GabrielF, Feb 20 '15 at 17:05
Have a look at the accepted answer here: https://stackoverflow.com/questions/22560588/c-string-to-integer-issue-using-atoistr-c-str — SukkoPera, Feb 20 '15 at 17:05
@SukkoPera: [This answer](http://stackoverflow.com/a/6154614/103167) is about 20 times better. — Ben Voigt, Feb 20 '15 at 17:10
If it's wrong, then how does it show your point? By your own admission, your code _doesn't do what you want it to do_. So, expecting us to be able to use it to magically divine what you want it to do, seems like quite optimistic thinking. — Lightness Races in Orbit, Feb 20 '15 at 17:16

score 0 · Accepted Answer · answered Feb 20 '15 at 17:09

0

As mentioned in the comments above, you can use std::stoi.

#include <iostream>
#include <string>
using namespace std;
int main ()
{
    string a;
    cin >> a;
    int b=10;
    cout << stoi(a)+b;
    return 0;
}

answered Feb 20 '15 at 17:09

shauryachats

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Have a string as an integer

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