Possible use of counter in function?

[sonic]

Have a quick question dealing with a program I've been working on all day. The program meets all the requirements for class and has displayed proper output through various tests. What I want to know is if i could use a counter of some sort in my printPattern function to count the total number of characters printed in the pattern. I have the logic worked out in my printLastLine function, but what if I had a program that had the possibility of going up to 1400 instead of just 14? The way I've currently coded the program would be rather inefficient and time consuming for one to hard code in. Like I said, I'm just curious for my own knowledge as I've already emailed my program in to my instructor.

 
// Program allows user to select number and type of pattern to be printed to screen
 
#include <iostream>
using namespace std;
 
// Function prototypes
 
void getInput(int&, char&);
void printError(int&, char&);
int printPattern(int, char);
void printLastLine(int, char);
 
int main()
{
    int numRows = 0;
    char typeChar = 0;
 
 
    getInput(numRows, typeChar);
    printPattern(numRows, typeChar);
    printLastLine(numRows, typeChar);
 
 
    return 0;
}
 
//************************************************************************
// Definition of getInput which obtains user info on how to build pattern*
//************************************************************************
 
void getInput(int& rows, char& characterSelect)
{
 
    cout << "How many rows do you want in the pattern (even numbers only: 2-14)? ";
    cin >> rows;
    cout << "What character do you want the pattern made of (select from: * + # or $)? ";
    cin >> characterSelect;
    printError(rows, characterSelect);
}
 
//************************************************************************
// Definition of printError which determines if user has entered         *
// acceptable input.                                                     *
//************************************************************************
 
void printError(int& rows, char& characterSelect)
{
 
    if ((rows < 2) || (rows > 14) || (rows%2 != 0))
    {
        cout << "\nInvalid number of rows. Please retry.\n";
        cout << "\n";
        system("pause");
        system("cls");
        getInput(rows, characterSelect);
    }
    else if ((characterSelect != '*') && (characterSelect != '+') && (characterSelect != '#') && (characterSelect != '$'))
    {
        cout << "\nInvalid character. Please retry using one of the four characters given.\n";
        cout << "\n";
        system("pause");
        system("cls");
        getInput(rows, characterSelect);
    }
 
}
 
//************************************************************************
// Definition of printPattern displays pattern based on user entered data*
// and tabulates the number of characters printed on screen.             *
//************************************************************************
 
int printPattern(int rows, char characterSelect)
{
    int halfValue = rows / 2;
 
for (int row = 0; row <= halfValue; row++)
    {    
        for(int character = 0; character < row; character++)
            cout << characterSelect;
            cout << "\n";
    }
 
    for (int row2 = halfValue; row2 >= 0; row2--)
    {
        for(int character2 = 0; character2 < row2; character2++)
            cout << characterSelect;
            cout << "\n";
    }
 
    return rows;
}    
 
//**********************************************************************
// Definition of printLastLine function displays to the user the number*
// of characters used to print the pattern as well as the type of      *
// character used.                                                     *
//**********************************************************************
 
void printLastLine(int numRows, char characterSelect)
{
    int totalCharacters = 0;
 
    if (numRows == 2)
        totalCharacters = 2;
    else if (numRows == 4)
        totalCharacters = 6;
    else if (numRows == 6)
        totalCharacters = 12;
    else if (numRows == 8)
        totalCharacters = 20;
    else if (numRows == 10)
        totalCharacters = 30;
    else if (numRows == 12)
        totalCharacters = 42;
    else if (numRows == 14)
        totalCharacters = 56;
 
    cout << "The total number of " << characterSelect << "'s displayed was " << totalCharacters << ".\n";
    cout << "\n";
}
 
 

Thanks for any thoughts or ideas.

[horace1]

try the following in the printLastLine() function

  int r=numRows/2;
  cout << "total characters " << ((r*(r+1))) << endl;
 

it should give you the number of total characters for any number of rows

it is a similar problem to calculating the storage requirements for a triangular matrix see
http://www.ncsa.uiuc.edu/UserInfo/Re...ml/essl43.html

[sonic]

Thank you for your input. The code worked like a charm. Now time for me to actually dig into how that formula actually works.