Arrays tutorial 1a

Program	Comments
//Arrays - Tutorial 1 #include <iostream> #include <iomanip>	We need iostream.h since we are using cout and we need iomanip.h (io manipulators header file) since we use the setw() manipulator.

{ int
   num[10][10], 
   totals[]
    = {0,0,0,0,0,0,0,0,0,0};
  int row, column;

The num array is declared as being a two-dimensional 10 X 10 array of integers. The totals array does not have a size declared but initialised to zeroes, the number of zeroes determines the size of totals. The integers row and column are used to count through the 2D array.

  for (row = 0; row < 10; row++) 
    for (column = 0; column < 10; column++)
      num[row][column] = row * column;

Array num is initialised to contain the product of the current values of row and column. A nested for loop is used, the program steps through in row order followed by column order.

  for (column = 0; column < 10; column++)
   for (row = 0; row < 10; row++) 
    totals[column] 
     = totals[column] + num[row][column];

Now the totalling of each column is completed. A nested for loop is used: for each row total the current column.

  for (row = 0; row < 10; row++)
   { cout << "....... "; 
     for (column = 0; column < 10; column++)
      cout << setw(4) << num[row][column];
     cout << endl;
   }

The rows and columns are displayed almost as for the original example. The difference is just the addition of the line:
cout << "....... ";

  cout << "Totals: ";

  for (row = 0; row < 10; row++)
   cout << setw(4)
        << totals[row];
       
  cout << endl;

  return 0;
}

Last of all the totals are shown, after the last row of the num array.

Return to the lesson

First Next Previous Last Glossary About