Gas Calc - gas.cpp

//NickG
//Gas Calculator

#include <iostream>
#include <iomanip>
using namespace std;

void validate (float* data) {
while(cin.fail()) { //Input validation loop
   cin.clear();  //Clear flags
   cin.ignore();  //Clear input buffer
   cout<<"Invalid Input - Please input a number:";
   cin>>(*data);
   }
}

int main () {
float gallons, miles, price, totalg, totalp, totalm, totalt;
char response;
cout << fixed << setprecision (2); //Set the output precision and output format

do { //Primary loop start
   do {
      if (gallons!=0)
      {cout << "Enter the gallons used:";}
      else //If gallons is 0, ask for a non-zero number
      {cout << "Enter a non-zero number:";}
      cin >> gallons;
      validate (&gallons);
      } while (gallons==0);
   cout << "Enter the miles driven:";
   cin >> miles;
   validate (&miles);
   cout << "Enter the price/gallon of gas:$";
   cin >> price;
   validate (&price);

   totalg+=gallons; //increment total gallons
   totalp+=(price*gallons); //increment total price
   totalm+=miles; //increment total miles
   totalt++; //increment total trips
   cout <<endl << "The mpg for this trip was " << miles/gallons << endl;
   cout << "The cost of this trip was $" << price*gallons << endl;

   do { //Response loop
      cout << "Would you like to calculate another trip? (y/n)";
      cin >> response;
      } while ((response!='y')&&(response!='Y')&&(response!='n')&&(response!='N')); //Wait for valid input
   cout << endl;
   } while ((response=='y')||(response=='Y')); //Primary loop end
cout << "Total miles traveled: " << totalm <<endl; //Print averages
cout << "Total price of trips: $" << totalp <<endl;
cout << "Total gallons of gas used: " << totalg <<endl;
cout << "The average miles driven was: " << totalm/totalt <<endl;
cout << "The average mpg was: " << totalm/totalg <<endl;
cout << "The average price of a trip was: $" << totalp/totalt <<endl;
#if defined (__WIN32__) || defined (__WIN32)
cout << "Press any key to continue...";
cin.ignore(255,'/n');
cin.get();
#endif
}