COM 1100 Fall 2000 -- Prof. Futrelle -- Lab 6 Directions

Using iteration and conditionals for pattern generation. String analysis.

Lab date: Wednesday November 8th. FLASH!! THIS LAB NOW DUE TUESDAY NOON, NOVEMBER 14^th
These directions were posted Wednesday, November 8^th.

SPECIAL NOTICE -- THIS CAN BE DONE AS A TEAM PROJECT WITH UP TO THREE PEOPLE, NO MORE. To do this, you must devote a great deal of attention to an extensive write-up that carefully explains what each member of the team did. This is not to be written in generalities, but must refer to specific strategies, code, debugging, testing, writing up, etc., that the various team members did. If there was serious sharing on some specific items, give an estimate of the percentage that each team member contributed to it. There may be more documentation of this type than actual code. That's as it should be. If there are two or three people on the team, I expect approximately two or three times as much work, total, e.g, 6 or 8 distinct patterns possibly including some complex ones.

Goal of the Lab #6:

Part A: To develop programs that use iteration (for and while) and conditionals (if) to generate patterns on the screen -- arrangements of characters such as the following:


*        *
* *      *
*  *     *
*   *    *
*    *   *
*     *  * 
*      * * 
*        *

Part B: To further use iterations and conditionals as well as simple string operations, to discover patterns in text such as determining that the following string has exactly 3 upper-case characters in it: "Gotta Tell You", or that the following string cannot be a proper Social Security Number "393938484A".

Generating Patterns on the screen:

The simplest way to describe what you'll be doing is to give a few code snippets that will produce some simple patterns.

This snippet:

int tot = 20;
for(int i = 0; i < tot; i++)
  {
  cout << '*';
  }

produces this:

********************

This snippet:

int tot = 20;
int gap = 5;
for(int i = 0; i < tot; i++)
  {
   if(i%gap == 0)
      cout << '*';
   else cout << ' ';
  }

produces this:

*    *    *    *

If the last snippet of code is placed inside another loop it can produce a pattern such as this:


*    *    *    *
*    *    *    *
*    *    *    *
*    *    *    *
*    *    *    *
*    *    *    *
*    *    *    *

Finally, we can arrange for the position of a character to depend on where in the outer loop it is (which line), so that this snippet of code:

  int width = 10;
  int height = 10;
  for(int h = 0; h < height; h++)
    {
    for(int i = 0; i < width; i++)
      {
        if(i == h)
          cout << '*';
        else cout << ' ';
      }
    cout << endl;
    }

will produce this pattern:

Note carefully that the first or "outer" for loop has a body that consists of the inner for loop, one for each line, followed by an endl for each line.

The directions for Part A of the lab assignment, pattern generation:

Assume you decide to produce four different patterns (the minimum will be three). Write a program that when it receives "h" as input (for help) will list the patterns it will produce along with a number or character that should be typed to cause a pattern to be printed.
The user should then input a pattern chooser (the number or letter) as well as an integer for the size of the pattern, e.g., a square that is 5 on a side or 12 on a side, etc.
The program will then display (print to the screen) the appropriate pattern of the correct size.
At a minimum, produce the three patterns below: The Square, Tic-Tac-Toe and N.
Your goal should be to maximize the use of simple functions to do the various tasks of deciding what to print, e.g., returning the correct character, getting input from the user, producing the help information, etc. You should depend as much as possible on iterations and tests to avoid explicit literal printing out of the pattern. You want to avoid things such as cout << "* * *" << endl << "* * *" << "* * *" << endl;

The patterns referred to in the directions are:

Square:

****************
*              *
*              *
*              *
*              *
*              *
*              *
*              *
****************

Tic-Tac-Toe:
 
    *     *  
    *     *  
    *     *      
***************
    *     *  
    *     *  
    *     *  
***************
    *     *  
    *     *  
    *     *  

N:

*        *
* *      *
*  *     *
*   *    *
*    *   *
*     *  * 
*      * * 
*        *

Extra credit: Try writing code that will produce a sine wave or a pattern such as this:

          *         
         * *             *         
        *   *           * *           *
       *     *         *   *         * *        *
      *********       *******       *****      *** 
          |              |            |         |
   -------------------------------------------------

The directions for Part B of the lab assignment, string analysis:

Write a program that accepts a string from the user, which may not have blanks in it (The Visual C++ system has a bug in getline()). Instead, it should have underscores where you would normally put blanks. I have a simpler and improved getline() function, replacing the earlier rough workaround. This will read lines with blanks so you might prefer to use it, the more standard approach.
The program will analyze the string, decide what category it belongs to (or none) and print out its decision.
The categories are defined as follows:
- A telephone number of the form XXX-XXX-XXXX where the Xs must be digits and the first one may not be a zero or 1. 10 digits all together.
- A Social Security number which may or may not have hyphens but which must have 9 digits.
- A proper name in which the first letter and each letter following an underscore is upper-case, e.g., "Hampsterdance_Song".
- A real number with digits and only one decimal point and possibly a leading minus sign.
- "Other" which means none of the above.
You'll find string functions discussed in Sec. 3.7 of your textbook. Also see the example below.

Here are some samples of code that do simple string analysis:

This snippet of code tells the user whether or not it has found an upper case letter in the string entered.

// COM 1100, Fall 2000, Prof. Futrelle
// Pattern generation and analysis
// l6.cpp, 11/06/2000

#include <iostream>
#include <string>

using namespace std;

void main()
{
  string input;
  cout << "Please enter a string (with no blanks -- underscores OK): ";
  cin >> input;
  int len = input.length();

  bool flag = false;
  char c;

  for(int i=0; i <len; i++)
    {
      c = input.at(i);
      if((c >= 'A') && (c <= 'Z'))
        flag = true;
    }


  if(flag) cout << "\n\nFound an upper-case character in: ";
  else cout << "\n\nNo upper-case characters found in : ";

  cout << input << endl;
}