Script started on Fri Sep 10 14:43:45 1999
strauss[2:43pm] [~/Class/cisc181/examples/]> cat 03-miles-per-gallon.cc

// Program calculates the miles per gallon 
// per tank of gas and overall given the 
// input data of miles driven and number 
// of gallons used for each tank 
// Exercise 2.16 from D&D
#include<iostream.h>

main ()
{
  float gallons, total_gallons, miles, 
        total_miles, mpg;

  // initialize
  total_gallons = 0;
  total_miles = 0;

  // initialize input (for sentinal value)
  cout << "Enter the gallons used (-1 to end): ";
  cin >> gallons;

  while (gallons != -1) 
    {
      if (gallons == 0)
	{
	  cout << "ERROR: gallons = 0, please try again";
	  cout << endl;
	}
      else
	{
	  total_gallons += gallons;
	  cout << "Enter the miles driven: ";
	  cin >> miles;
      	  total_miles += miles;
	  cout << "The miles / gallon for this tank was " 
	       << ( miles / gallons) << endl;
	  cout << endl;
	}
      cout << "Enter the gallons used (-1 to end): ";
      cin >> gallons;
    }
  
  // Summation Phase
  if (total_gallons != 0)
    {
      cout << endl;
      cout << "The ovrall average miles / gallon was " 
	   << (total_miles / total_gallons)
	   << endl;
    }

  return 0;
}
strauss[2:43pm] [~/Class/cisc181/examples/]> CC 03-,miles-per-gallon.cc

strauss[2:44pm] [~/Class/cisc181/examples/]> a.out

Enter the gallons used (-1 to end): 5
Enter the miles driven: 23
The miles / gallon for this tank was 4.6

Enter the gallons used (-1 to end): 20
Enter the miles driven: 400
The miles / gallon for this tank was 20

Enter the gallons used (-1 to end): 17
Enter the miles driven: 36.4
The miles / gallon for this tank was 2.14118

Enter the gallons used (-1 to end): 0
ERROR: gallons = 0, please try again
Enter the gallons used (-1 to end): -1

The ovrall average miles / gallon was 10.9381
strauss[2:45pm] [~/Class/cisc181/examples/]> 

strauss[2:45pm] [~/Class/cisc181/examples/]> a.out

Enter the gallons used (-1 to end): -1
strauss[2:45pm] [~/Class/cisc181/examples/]> a.out

Enter the gallons used (-1 to end): 20
Enter the miles driven: 400
The miles / gallon for this tank was 20

Enter the gallons used (-1 to end): 10.3
Enter the miles driven: 200
The miles / gallon for this tank was 19.4175

Enter the gallons used (-1 to end): -1

The ovrall average miles / gallon was 19.802
strauss[2:46pm] [~/Class/cisc181/examples/]> exit

strauss[2:46pm] [~/Class/cisc181/examples/]> exit

script done on Fri Sep 10 14:46:32 1999