/*
 * My first program that wasn't from a tutorial.
 * (C) 2007 Laseredd.
 */
 
#include <iostream>
#include <string>
#include <sstream>
using namespace std; 
 
class Calc 
{
	int num1, num2;
   	public:
   	void set_num(int, int);
   	int add();
};
 
void Calc::set_num(int a, int b)
{
	num1 = a;
	num2 = b;
}
 
int Calc::add()
{
	return (num1 + num2);
}
 
int main()
{
	Calc calc;
	string valid;
	int numb1, numb2;
 
	cout << "What numbers to you want to add? " << endl;
 
	cout << "Number 1: ";
	getline(cin, valid);
	stringstream(valid) >> numb1;
 
	cout << "Number 2: ";
	getline(cin, valid);
	stringstream(valid) >> numb2;
 
	calc.set_num(numb1, numb2);
	cout << calc.add();
 
	return 0;
}

#include <iostream>
#include <algorithm>
#include <sstream>
 
using namespace std;
 
struct nondigit
{
public:
    bool operator() (char ch)
    {
        return !isdigit(ch);
    }
};
 
 
int main()
{
    int num;
    string str;
    bool flag=false;
    cout<< "Enter number: "<< endl;
    cin>>str;
 
    //make sure that num contains digits exclusively
    if(find_if(str.begin(),str.end(), nondigit())==str.end())
        flag=true; // we have a valid string
    else
        cout<<"Invalid Input";
 
    if(flag==true)
    {
        stringstream temp(str); //insert string to temp
        temp>>num; //extract int value and write it to num
        cout<<num;
    }
 
    return 0;
}