// initializing C++
#include <iostream>
using namespace std; // declaring function prototypes float addition (float a, float b);
//main function
int main () {
    float x; //
    float y; //declares variables
    float n; //
    int op;
    int b;
    b = 1; //sets value of b to 1
    cout << "vaati and Canti's collaborative learning calc. For teaching vaati ;P"; //displays info about program
    while (b==1) //creates loop so the program runs as long as the person wants to add numbers
    {
        //following code prompts the user for 2 numbers to add and calls function addition to display results
        cout << "\n" << "Type a number to manipulate (can also use negetive, decimals, etc.) addition and subtraction only.: ";
        cin >> x;
 
        cout << " Second number: ";
        cin >> y;
 
        cout << "What do you want to do with these? (1=addition, 2=subtract 3=leave program): ";
        cin >> op;
 
        switch(op){
          case 1:
          cout << "Ans: " << x << " + " << y << " = " << x + y << "\n";
          break;
          case 2:
          cout << "Ans: " << x << " - " << y << " = " << x - y << "\n";
          break;
          default:
          cout<<"Not a valid operation\n";
        }
        //following code sets b to the value the user inputs to determine if the loop is broken to end the program
        cout << "Solve another operation? Or leave? (1=Continue, 2=Exit): ";
        cin >> b;
        cout << "\n";
    }
    return 0;
    //ends the main function of the code
}

#include <iostream>
#include <cctype>
#include <string>
#include <cstdlib>
using namespace std;
 
 
int main ()
{
    int number;
    string input;
 
    bool inputIsInvalid;
 
    do
    {
         inputIsInvalid = false;
         cout << "Please enter an integer : ";
         cin >> input;
 
         // verify input
         int stringLength = input.length ();
 
         // test each character.  If any characters fail, it's bad input
         for (int i = 0; i < stringLength; i++)
         {
             // test a character.  Legal characters are digits and '-'.
             char aCharacter = input[i];
             if (aCharacter != '-' && !isdigit (aCharacter))
             {
                 inputIsInvalid = true;
             }
         }
 
         if (inputIsInvalid)
         {
             // error message
             cout << "Oops.  Bad input.  Please try again." << endl;
         }
    }
    while (inputIsInvalid);
 
    number = atoi (input.c_str ());
 
    cout << "You entered " << number << endl;
 
    return 0;
}