#include <iostream>
#include <string>
#include <iomanip>
#include <fstream>
#include <math.h>

using namespace std;
int main()
{
    // Declare Necessary Variables

    float Vot = 0;
    float Vi = 0;
    float e = 0;
    float Voe = 0;
    char a = 0;


do {
    cout << "Measured Input  Voltage = " << Vi << endl << "Measured Output Voltage = " << Voe << endl << "Error Rate = " << e << endl << "Result = " << Vot << endl << endl << endl << endl;
    cout << "(I) Change Input Voltage " << endl << "(O) Change Output Voltage" << endl << "(E) Exit " << endl << endl;
    cout << "Choose option" << endl;
    cin >> a;


switch ( a )
      {
         case 'I':
         system("CLS");
         cout << "Input Voltage = ";
         cin >> Vi;
         break;
         case 'i':
         system("CLS");
         cout << "Input Voltage = ";
         cin >> Vi;
         break;
         case 'O':
         system("CLS");
         cout << "Output Voltage = ";
         cin >> Voe;
         break;
         case 'o':
         system("CLS");
         cout << "Output Voltage = ";
         cin >> Voe;
         break;
         default:
          break;
      }
    Vot = 10 - 5 * (pow( Vi - 1.5, 2));
    e = ((Voe-Vot)/Vot)*100;
system("CLS");
}while ( a != 'E' && a != 'e');


}