converting string to int!

I got only one error that I do not know how to get it fixed!

Code:

---

#include <iostream>
using namespace std;

int main(){
string num;
int i = 0;
       
       
        cout << "Insert a number between 10-99"<<endl;
        cin >> num;
       
  i = atoi(num);
       
        if ((i > 9) && (i < 100)){
                cout << "The Inverse number of the input is    " << num[1]<< num[0] << endl;
        }
        else{
                cout << "ERROR: You must select a number between 10-99" << endl;
        }
       
        return 0;
}

---

You're missing a bunch of header files.
I'd recommend using a stringstream to convert between strings & numbers though.

Code:

---

std::stringstream ss;
ss << "666";
int num;
ss >> num;

---

Of course you'd also want to do some checking to see if the conversion failed...

atoi() takes a c-string as input

Code:

---

  i = atoi(num.c_str());

---

Quote:

---

Originally Posted by cyberfish

atoi() takes a c-string as input

Code:

---

  i = atoi(num.c_str());

---

---

And atoi() is not a particularly "user friendly" function, as there's nearly no way to determing if the input was rubbish or valid data. If you must use non-stringstream functions, use strtol().

--
Mats

Try converting string to float. You should also validate like for example the string cannot have more than 1 decimal point. The string should be a valid number etc.And yeah most importantly... don't use atof() function! ;)