// SquareDemo - demostrate the use of a function
//              which processes arguments

#include <stdio.h> 
#include <iostream.h>

// square - returns the square of its argument
//          dVar - the value to be squared
//          returns - sqare of dVar
double square(double dVar)
{
    return dVar * dVar;
}

int sumSequence(void)
{
    // loop forever
    int nAccumulator = 0;
	for(;;)
	{
        // fetch another number
	    double dValue = 0;
	    cout << "Enter next number: ";
	    cin  >> dValue;

        // if it's negative...

	    if (dValue < 0)
	    {
            // ...then exit from the loop
		    break;
        }

        // ...otherwise calculate the square
        int nValue = (int)square(dValue);

        // now add the square to the
        // accumulator
        nAccumulator = nAccumulator + nValue;
	}

    // return the accumulated value
    return nAccumulator;
}

int main(int nArg, char* pszArgs[])
{
    cout << "This program sums multiple series\n"
         << "of numbers. Terminate each sequence\n"
         << "by entering a negative number.\n"
         << "Terminate the series by entering two\n"
         << "negative numbers in a row\n";

    // Continue to accumulate numbers...
    int nAccumulatedValue;
    do
    {
        // sum a sequence of numbers entered from
        // the keyboard
        cout << "\nEnter next sequence\n";
        nAccumulatedValue = sumSequence();

	    // now output the accumulated result
	    cout << "\nThe total is " 
             << nAccumulatedValue 
             << "\n";

    // ...until the sum returned is 0
    } while (nAccumulatedValue != 0);
    cout << "Program terminating\n";
    return 0;
}