Expert: Zlatko - 8/13/2010

Question
Hi Zlatko, What I really want is a display like this:

                     ROWS     (0)     (1)     (2)     (3)     (4)
 -----------------------------------------------------
                          0)       1      13      23      45      50
                          1)       5      12      34      36      51
                          2)       2      23      25      46      54
                          3)       2       7      35      39      48
                          4)      34       5      26      39      49

   Enter the number you are searching for in column (0): 2

                                 NUMBER 2 in COLUMN (0) in 5 ROWS                      
===============================================

                                ROWS     (0)     (1)     (2)     (3)     (4)
         -----------------------------------------------------
                                     2)       2      23      25      46      54
                                     3)       2       7      35      39      48

   Enter the number one (1): 1

                                 NUMBERS THAT ARE NOT IN THE MATRIX
                                    BETWEEN THE NUMBERS 1 AND 56                              
============================================

 1  3  4  5  6  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  24  26  27  
28  29  30  31  32  33  34  36  37  38  40  41  42  43  44  45  47  49  50  51  52  
53  55  56

   If you see, I displayed all the numbers between 1 and 56 not present in the
following matrix:
                           NUMBER 2 in COLUMN (0) in 5 ROWS
                     
                           ROWS     (0)     (1)     (2)     (3)     (4)
    -----------------------------------------------------
                                2)       2      23      25      46      54
                                3)       2       7      35      39      48
   This is the code I used to get that:

if (foundInFirstCol)
      {
          cout<<"    Enter the number one (1): ";
          cin>>Number;
          cout<<setw(70)<<"NUMBERS THAT ARE NOT IN THE MATRIX \n";
          cout<<setw(66)<<"BETWEEN THE NUMBERS 1 AND 56\n";
          
cout<<setw(75)<<"===================================
=========\n\n";

          do{
          bool foundInMatrix = false;
          for(int i=0; i< rows && !foundInMatrix; i++)
          {
              for(int j = 0; j < columns && !foundInMatrix; ++j)
              {
                  if(array[2][j]==Number||    // I used this code just to show you what
                     array[3][j]==Number)     // I really want to display
                  {
                      foundInMatrix = true;
                  }
              }
          }
          if (! foundInMatrix)
          {
              cout<<"  "<<Number;
          }
          Number++;
      }while(Number<=56);
      }
   
   THANKS.


Answer
Hello Raul. I think I understand your question now.

Step 1) The program asks for a number. Then it returns all the rows that have that number in column 0.

Step 2) The program prints out all numbers between 1 and 56 which are not in the rows returned in step 1.

A simple and efficient way of doing this is to make an array of 57 integers. Go through the rows returned from step 1, and for each number (i), set array[i] = 1. In the end, if element i is not 0, it means that i is in the matrix. Then go through the array and print out all i where array[i] is 0.

The code below does it. I hope it is clear enough.  

#include <iostream>
#include <iomanip>

int rows=5;
int columns=5;
int  minWishedNumber=1;
int  maxWishedNumber=56;
int wishedNumber;

using namespace std;

int getWishedNumber();
void displayRows(int array[], int index);
void printHeading();

int main()
{
   cout<<endl;
   char choice;
   int array[5][5]={{2,13,23,45,50},
   {5,12,34,36,51},
   {2,23,25,46,54},
   {2,7,35,39,48},
   {3,5,26,39,49}};

   printHeading();
   for(int i=0; i<rows; i++)
   {
       cout<<setw(19)<< i <<")";
       for(int j=0; j<columns; j++)
       {
           cout<<setw(8)<<array[i][j];
       }
       cout<<endl;
   }
   do
   {
       getWishedNumber();
       cout<<endl<<endl;
       cout<<setw(33)<<"NUMBER "<<wishedNumber<<" in COLUMN (0) in " <<rows<<" ROWS."<<endl;
       printHeading();
       cout<<endl;

       /*
       The foundList will record which numbers are in the matrix.
       If foundList[i] is not 0, it means that i is in the matrix.
       */
       int foundList[57];
       memset(foundList, 0, sizeof(foundList));
       bool foundInFirstCol = false;

       /* Check if the wished number is in the first column */
       for(int i=0; i< rows; i++)
       {
           if(array[i][0]==wishedNumber)
           {
               cout<<setw(19)<< i <<")";
               displayRows(array[i], columns);
               foundInFirstCol = true;
               /*
               For the row that has the wishedNumber in the first column,
               examine all the elements in that row and record them in the foundList
               */
               for(int col = 0; col < columns; ++col)
               {
                   foundList[array[i][col]] = 1;
               }
           }
       }

       if (foundInFirstCol)
       {
           /* Print out the elements not in the foundList */
           cout << "NUMBERS THAT ARE NOT IN THE RETURNED MATRIX\n"
               "BETWEEN THE NUMBERS 1 AND 56\n"
               "============================================\n";
           int count = 0;
           for(int i = 1; i < 57; ++i)
           {
               if (foundList[i] == 0)
               {
                   cout << setw(3) << i;
                   /* print out 10 to a line */
                   if (++count % 10 == 0) cout << endl;
               }
           }
           cout << endl;
       }
       else
       {
           cout << "NUMBER " << wishedNumber << " is not in the first column\n";
       }

       cout<<endl;
       cout<<"\n    Would you like to look up another ";
       cout<<"number in column (0)? (y/n): ";
       cin >> choice;

   }  while (choice == 'y'|| choice == 'Y');
   cout<<endl;
   return 0;
}
int getWishedNumber()
{
   cout<<"\n    Enter the number you are searching for in column (0): ";
   cin >> wishedNumber;

   while (wishedNumber < minWishedNumber || wishedNumber >
       maxWishedNumber)
   {
       cout<<"\n    I'm sorry, enter a number in the range of " <<
           minWishedNumber;
       cout <<" through " << maxWishedNumber << ": ";
       cin >> wishedNumber;
       cout<<endl;
   }
   return wishedNumber;
}
void displayRows(int array[], int index)
{
   for( int i=0; i < columns; i++)
   {
       cout << setw(8) << array[i];
   }
   cout << endl;
}
void printHeading()
{
   cout<<setw(68)<<"=====================================================\n\n";
   cout<<setw(61)<<"ROWS     (0)     (1)     (2)     (3)     (4)"<<endl<<endl;

}