C++ Output Statements
To place the results of computations or the current contents of a memory location on the standard output device (usually the screen), we use a special variable called cout along with the insertion operator ( << ). For example:

cout << "Welcome to 2170" << endl;

This statement displays the string of characters Welcome to 2170 on the "standard output device", usually the monitor screen. A string is a sequence of characters enclosed in double quotes; the characters inside the quotes will be printed but the quotes will not be printed. The identifier endl (meaning "end line") is a special C++ feature called a manipulator. We will discuss manipulators in a later lab. For now, just remember that endl lets you finish an output line. As a second example:

cout << "Welcome" << endl;

cout << "to 2170" << endl;

cout << "Your age is " << age << endl;

displays two items; the character string "Your age is" and the value of age. If age contained the value 21, then the output would appear as:

Your age is 21

Character and String Data Types
In addition to numeric data, character data may also be placed in memory. To declare a variable which can contain a single character value, use the C++ reserved word char. Suppose we wished to declare the variables initial1 and initial2 to contain any single character value. We would use:

char initial1, initial2;

Values can be placed into the variables using assignment statements or cin.

initial1 = 'J';
initial2 = 'K';

places the characters J and K into the two variables respectively.

Code for Lab 3 (Do not copy/paste)

1	// File Name:  cla3a.txt
2	// Purpose:    This program calculates a landlord's earnings
3	//             on an apartment given the rent per month, the
4	//             number of months rented and a deduction of 5%
5	//             commission for an overseer.
6
7	#include <iostream>
8	using namespace std;
9
10	const float RATE = 0.05;      // overseer's commission rate
11	float CalcEarnings (float rent, int numMonths);
12	void printResults (string last, char middle, string first,
13	                   float rent, int numMonths, float earnings);
14
15	int main()
16	{
17	     //variable declarations...
18	     float rent;             // rent per month
19	     int   numMonths;        // number of months rented
20	     float earnings;         // earnings on the apartment
21	     string lastName;        // the last name of the tenant
22	     char   middleInitial;   // the middle initial of the tenant
23	     string firstName;       // the first name of the tenant
24
25	     //set values for apartment renter, rent/month and number of months
26	     //the apartment has been rented.
27	     lastName = "Smith";
28	     middleInitial = 'A';
29	     firstName = "Jill";
30	     rent = 350.00;
31	     numMonths = 12;
32
33	     //calculate earnings
34	     earnings = CalcEarnings (rent, numMonths);
35
36	     // display results
37	     PrintResults (lastName, middleInitial, firstName, rent, numMonths, earnings);
38
39	     //exit
40	     return 0;
41	}
42
43	//This function calculates the earnings for an
44	//apartment.
45	float CalcEarnings (float rent, float numMonths)
46	{
47	     return (1.0 - RATE) * rent * numMonths;
48	}
49
50	//This function displays all of the apartment information
51	void PrintResults (string last, char middle, string first,
52	                   float rent, int numMonths, float earnings);
53	{
54	     cout << "The name of the apartment renter is: "
55	           << first << " " << middle << " " << last << endl;
56	     cout << "The rent per month is: " << rent << endl;
57	     cout << "The apartment has been rented for ";
58	     cout << numMonths << " months." << endl;
59	     cout << "The overseer receives a " << 100 * RATE;
60	     cout << "% commission rate. " << endl;
61	     cout << "The earnings were: " << earnings << endl;
61	}



// File:            cla3b.cpp
// Author:
// Purpose:         This program calculates a landlord's earnings
//                  on an apartment given the rent per month, the
//                  number of months rented and a deduction of 5%
//                  commission for an overseer.  

#include <iostream>
using namespace std;

int main()
{
     //variable and constant declarations...
     const float RATE = 0.05;      // overseer's commission rate
     float rent;                   // rent per month
     float numMonths;              // number of months rented
     float earnings;               // earnings on the apartment

     //assign values and calculate earnings
     rent = 250;
     numMonths = 7;

     //calculate earnings
     earnings = (1.0 - RATE) * rent * numMonths;

     // display results
     cout << "The rent per month is: " << rent << endl;
     cout << "The apartment has been rented for ";
     cout << numMonths << " months." << endl;
     cout << "The overseer receives a " << 100 * RATE;
     cout << "% commission rate. " << endl;
     cout << "The earnings were: " << earnings << endl;

     //exit
     return 0;
}



// File:            cla3c.cpp
// Author:
// Purpose:         This program calculates a landlord's earnings
//                  on an apartment given the rent per month, the
//                  number of months rented and a deduction of 5%
//                  commission for an overseer.  Initials for the
//                  apartment renter are also output.

#include <iostream>
using namespace std;

int main()
{
     //variable and constant declarations...
     const float RATE = 0.05;      // overseer's commission rate
     float rent;                   // rent per month
     float numMonths;              // number of months rented
     float earnings;               // earnings on the apartment
     char firstInitial,
          middleInitial,
          lastInitial;             // initials of the apartment renter

     //assign values and calculate earnings
     rent = 250;
     numMonths = 7;
     firstInitial = 'J';
     middleInitial = 'A';
     lastInitial = 'C';

     //calculate earnings
     earnings = (1.0 - RATE) * rent * numMonths;

     // display results
     cout << "The initials of the apartment renter are: "
          << firstInitial << middleInitial << lastInitial << endl;
     cout << "The rent per month is: " << rent << endl;
     cout << "The apartment has been rented for ";
     cout << numMonths << " months." << endl;
     cout << "The overseer receives a " << 100 * RATE;
     cout << "% commission rate. " << endl;
     cout << "The earnings were: " << earnings << endl;

     //exit
     return 0;
}