Exercise 5.2 (Completed)

1. (Modify) Rewrite Program 5.6 to compute the total of eight numbers.
#include <iostream>
using namespace std;
int main()
{
  const int MAXNUMS = 8;
  int count;
  double num, total;
  cout << “\nThis program will ask you to enter “
       << MAXNUMS << “ numbers.\n”;
  count = 1;
  total = 0;
  while (count <= MAXNUMS)
  {
    cout << “\nEnter a number: “;
    cin  >> num;
    total = total + num;
    cout << “The total is now “ << total;
    count++;
  }
  cout   << “\n\nThe final total is “ << total << endl;
  return 0;
}
2. (Modify) Rewrite Program 5.6 to display this prompt:
Please type in the total number of data values to be added:
In response to this prompt, the program should accept a user-entered number, and then use it
to control the number of times the while loop is executed. So if the user enters 5 in response
to the prompt, the program should request the input of five numbers and display the total after
five numbers have been entered.

#include <iostream>
using namespace std;
int main()
{


		 int MAXNUMS;
			int count;
			double num, total;
			cout << "Please type in the total number of dat values to be added : ";
			cin >> MAXNUMS;
			cout << "\nThis program will ask you to enter "

			<< MAXNUMS << " numbers.\n";

			count = 1;
			total = 0;
			while (count <= MAXNUMS)
			{
					cout << "\nEnter a number : ";
				    cin >> num;
					total = total + num;
					cout << "The total is now " << total;
					count++;
			}
			cout << "\n\nThe final total is "<< total << endl;

	system("PAUSE");
	return 0;
}

3. (Modify) Rewrite Program 5.7 to compute the average of 10 numbers.

#include <iomanip>
#include <math.h>       /* pow & sqrt */
#include <iostream>
using namespace std;
int main()
{


	const int MAXNUMS = 10;
	int count;
	double num, total, average;

	cout << "\nThis program will ask you to enter "
		<< MAXNUMS << "numbers.\n\n";
	count = 1;
	total = 0;
	while (count <= MAXNUMS)
	{
		cout << "Enter a number : ";
		cin >> num;
		total = total + num;
		count++;
	}
	count--;
	average = total / count;
	cout << "\nThe average of the numbers is "
		<< average << endl;
	system("PAUSE");
	return 0;
}

4. (Modify) Rewrite Program 5.7 to display the following prompt:
Please type in the total number of data values to be averaged:
In response to this prompt, the program should accept a user-entered number, and then use it
to control the number of times the while loop is executed. So if the user enters 6 in response
to the prompt, the program should request an input of six numbers and display the average of
the next six numbers entered.

#include <iostream>
using namespace std;
int main()
{
  int MAXNUMS;
	int count;
	double num, total, average;
  cout << "Pleae type in the totla number of data values to be averaged:" << endl;
  cin >> MAXNUMS;
	cout << "\nThis program will ask you to enter "
		<< MAXNUMS << "numbers.\n\n";
	count = 1;
	total = 0;
	while (count <= MAXNUMS)
	{
		cout << "Enter a number : ";
		cin >> num;
		total = total + num;
		count++;
	}
	count--;
	average = total / count;
	cout << "\nThe average of the numbers is "
		<< average << endl;
	system("PAUSE");
	return 0;
}
5. (Debug) By mistake, a programmer puts the statement average = total / count; in the
while loop immediately after the statement total = total + num; in Program 5.7. As a
result, the while loop becomes the following:

while (count <= MAXNUMS)
{
  cout << “Enter a number: “;
  cin  >> num;
  total = total + num;
  average = total / count;
  count++;
  
}
a. Will the program yield the correct result with this while loop?

Yes, the program yields the correct results because the last time through the loop, it takes
the average of the final total.

b. From a programming perspective, which while loop is better to use, and why?

Having the average calculate outside the loop is better because the program does the calculation
once instead of each time the loop executes.

6. (Program) a. Write a C++ program to convert meters to feet. The program should request the
starting meter value, the number of conversions to be made, and the increment between metric
values. The display should have appropriate headings and list the meters and corresponding
feet value. If the number of iterations is greater than 10, have your program substitute a
default increment of 10. Use the relationship that 1 meter = 3.281 feet.
#include <iostream>
using namespace std;
int main()
{
		
			int Startmeters;
			int Maxnumber;
			int increment;
			double feet,meters;

			cout << "Enter starting meter value" << endl;
			cin >> Startmeters;
			cout << "Enter the number of conversions to be made" << endl;
			cin >> Maxnumber;
			cout << "Enter the increment between metric values" << endl;
			cin >> increment;
			if (increment > 10){
				increment = 10;
			}
			meters = Startmeters;

			while (meters <= Maxnumber){
			
				
				 feet = meters * 3.2808399;
				cout << meters << endl;
				cout << feet << endl;
				meters = meters + increment;
			}
	system("PAUSE");
	return 0;
}

b. Run the program written in Exercise 6a on a computer. Verify that your program begins at
the correct starting meter value and contains the exact number of conversions specified in
your input data.
Done!!
7. (Modify) a. Modify the program written in Exercise 6a to request the starting meter value,
the ending meter value, and the increment. Instead of the condition checking for a fixed
count, it checks for the ending meter value. If the number of iterations is greater than 20, have
your program substitute a default increment of (ending value - starting value) / 19.

#include <iostream>
using namespace std;
int main()
{
		
			int Startmeters;
			int Maxnumber;
			int increment;
			double feet,meters;

			cout << "Enter starting meter value" << endl;
			cin >> Startmeters;
			cout << "Enter the number of conversions to be made" << endl;
			cin >> Maxnumber;
			cout << "Enter the increment between metric values" << endl;
			cin >> increment;
			if ((Maxnumber - Startmeters) > 20)
			{
				increment = ((Maxnumber - Startmeters) / 19);
			}
			meters = Startmeters;

			while (meters <= Maxnumber){
			
				
				 feet = meters * 3.2808399;
				cout << meters << endl;
				cout << feet << endl;
				meters = meters + increment;
			}
	system("PAUSE");
	return 0;
}

b. Run the program written in Exercise 7a on a computer. Verify that your output starts at the
correct beginning value and ends at the correct ending value.
Done!!
8. (Program) a. Write a C++ program to convert Celsius degrees to Fahrenheit. The program
should request the starting Celsius value, the number of conversions to be made, and the
increment between Celsius values. The display should have appropriate headings and list the
Celsius value and the corresponding Fahrenheit value. Use the relationship that Fahrenheit =
(9.0 / 5.0) * Celsius + 32.0.

#include <iostream>
using namespace std;
int main()
{
		
			int StartCelsius;
			int Maxnumber;
			double increment;
			double Celsius, Fahrenheit;

			cout << "Enter starting Celsius value" << endl;
			cin >> StartCelsius;
			cout << "Enter the number of conversions to be made" << endl;
			cin >> Maxnumber;
			cout << "Enter the increment between metric values" << endl;
			cin >> increment;
			
			
			Celsius = StartCelsius;

			while (Celsius <= Maxnumber){
				 
				Fahrenheit = ((9.0 / 5.0) * Celsius + 32.0);
				cout << Celsius << endl;
				cout << Fahrenheit << endl;
				Celsius = Celsius + increment;
			}
	system("PAUSE");
	return 0;
}
b. Compile and run the program written in Exercise 8a on a computer. Verify that your program
begins at the correct starting Celsius value and contains the exact number of conversions
specified in your input data.
Done!!
9. (Program) An arithmetic series is defined by the following:
a + (a + d ) + (a + 2d ) + (a + 3d ) + ˙˙˙ + [(a + (n - 1)d )]
a is the first term.
d is the “common difference.”
n is the number of terms to be added.
Using this information, write a C++ program that uses a while loop to display each term and
determine the sum of the arithmetic series having a = 1, d = 3, and n = 100. Make sure your
program displays the value it has calculated.

#include <iostream>
using namespace std;
int main()
{
		
			int Startnum = 1;
			int Maxnumber = 100;
			double increment = 1;
			double a=1,d=3,n,Solution;

			n = Startnum;

			while (n <= Maxnumber){
				Solution = (a + (n - 1)*d);
				cout << a << endl;
				cout << d << endl;
				cout << n << endl;
				cout << Solution << endl;
				n = n + increment;
			}
	system("PAUSE");
	return 0;
}
10. (Program) A geometric series is defined by the following:
a + ar + ar 2 + ar 3 + ˙˙˙ + ar n - 1
a is the first term.
r is the “common ratio.”
n is the number of terms in the series.
Using this information, write a C++ program that uses a while loop to display each term and
determine the sum of a geometric series having a = 1, r = .5, and n = 10. Make sure your program
displays the value it has calculated.
#include <iostream>
using namespace std;
int main()
{
		
			int Startnum = 1;
			int Maxnumber = 10;
			double increment = 1;
			double a=1,r=.5,n,Solution;

			n = Startnum;

			while (n <= Maxnumber){
				Solution = pow((a*r ) ,(n - 1));
				cout << a << endl;
				cout << r << endl;
				cout << n << endl;
				cout << Solution << endl;
				n = n + increment;
			}
	system("PAUSE");
	return 0;
}
11. (Program) a. The data in the following chart was collected on a recent automobile trip:
Mileage Gallons
22,495 Full tank
22,841 12.2
23,185 11.3
23,400 10.5
23,772 11.0
24,055 12.2
24,434 14.7
24,804 14.3
25,276 15.2
Write, compile, and run a C++ program that accepts a mileage and gallons value and calculates
the miles per gallon (mpg) for that segment of the trip. The mpg is calculated as the difference
in mileage between fill-ups divided by the number of gallons of gasoline used in the fill-up.

#include <iostream>
using namespace std;
int main()
{
		
			double startmil = 22495;
			double endmil = 25276;
			double increment = 200;
			double Mileage,fill_up = 15,mpg;

			Mileage = startmil;

			while (Mileage <= endmil){

				mpg = ((endmil - startmil) / (fill_up));
				cout << fill_up << endl;
				cout << Mileage << endl;
				cout << mpg << endl;
				 Mileage = Mileage + increment;
			}
	system("PAUSE");
	return 0;
}

b. Modify the program written for Exercise 11a to also compute and display the cumulative
mpg after each fill-up. The cumulative mpg is calculated as the difference between mileage
at each fill-up and mileage at the start of the trip divided by the sum of gallons used to that
point in the trip.
#include <iostream>
using namespace std;
int main()
{
		
			double startmil = 22495;
			double endmil = 25276;
			double increment = 200;
			double Mileage,fill_up = 15,mpg,cumulativemil,currentgal = 2.5;

			Mileage = startmil;

			while (Mileage <= endmil){
				currentgal = currentgal + fill_up;
				cumulativemil = (endmil - Mileage) / (currentgal);
				mpg = ((endmil - Mileage) / (fill_up));
				cout << Mileage << endl;
				cout << cumulativemil;
				cout << Mileage << endl;
				cout << mpg << endl;
				 Mileage = Mileage + increment;

			}
	system("PAUSE");
	return 0;
}
12. (Program) a. A bookstore summarizes its monthly transactions by keeping the following
information for each book in stock:
Book identification number
Inventory balance at the beginning of the month
Number of copies received during the month
Number of copies sold during the month
Write a C++ program that accepts this data for each book and then displays the book identification
number and an updated book inventory balance, using this relationship:
New balance = Inventory balance at the beginning of the month
+ Number of copies received during the month
- Number of copies sold during the month
Your program should use a while statement with a fixed-count condition so that information
on only three books is requested.

#include <iostream>
using namespace std;
int main()
{
		
			double start = 1;
			double end = 3;
			double increment = 1,newBal,invBal,numCopRec,numCopsold,id;
			
			cout << "Inventory balance at the beginning of the month" << endl;
			cin >> invBal;
			cout << "Book identification number" << endl;
			cin >> id;
			cout << "Number of copies received during the month" << endl;
			cin >> numCopRec;
			cout << "Number of copies sold diring the month" << endl;
			cin >> numCopsold;
			id = start;

			while (id <= 3){
				invBal = (invBal + numCopRec - numCopsold);
				cout << id << endl;
				cout << invBal << endl;
				 id = id + increment;
		
			}
	system("PAUSE");
	return 0;
}

b. Compile and run the program written in Exercise 12a. Review the display your program
produces and verify that the output is correct.
Done!!
13. (Modify) Modify the program you wrote for Exercise 12 to keep requesting and displaying
results until a sentinel value of 999 is entered. Compile and run your program. Review the
display your program produces and verify that the output is correct.

#include <iostream>
using namespace std;
int main()
{
		
			double start = 1;
			double end = 999;
			double increment = 1,newBal,invBal,numCopRec,numCopsold,id;
			
			cout << "Inventory balance at the beginning of the month" << endl;
			cin >> invBal;
			cout << "Book identification number" << endl;
			cin >> id;
			cout << "Number of copies received during the month" << endl;
			cin >> numCopRec;
			cout << "Number of copies sold diring the month" << endl;
			cin >> numCopsold;
			id = start;

			while (id <= 999){
				invBal = (invBal + numCopRec - numCopsold);
				cout << id << endl;
				cout << invBal << endl;
				 id = id + increment;
		
			}
	system("PAUSE");
	return 0;
}