/* This program asks the user for an odd integer bigger than or equal to 5,
   and then prints the pattern of a box with an X in it to the screen, made
   out of + signs.  So if the user enters in 7, the output should be

+++++++
++   ++
+ + + +
+  +  +
+ + + +
++   ++
+++++++

  The program is implemented using several functions.  3 different functions
  print out different sorts of lines in the picture: (1) the top and bottom
  lines are solid +'s, (2) the middle line contains 3 +'s, and (3) the other
  lines contain 4 +'s.  There's also a function to print out blank spaces,
  as used in the lines of type (2), (3) above.
*/


#include <iostream.h>

void solid_line (int);
void blank_space (int);
void write_line (int, int);
void mid_line (int);

void main() {

  int side, row, count = 0;

  /* The following loop cycles until the user enters an odd integer >=5.
     The count variable is used to avoid an infinite loop. */

  do {
    cout << "Enter an odd integer bigger than or equal to 5: ";
    cin >> side;
    count++; if (count>=10) break;
  }
  while ((side%2==0) || (side < 5));

  cout << endl;

  solid_line(side);  // top row;

  for (row=2; row <= (side - 1)/2; row++) write_line(row, side);

  mid_line(side);   // conceptually, row is (side +1)/2, the middle row

  for (row=(side+3)/2; row<side; row++) write_line(side-row+1, side);

  solid_line(side);   // bottom row
}


void solid_line (int m)  // prints m +'s to the screen, then an endl
{
  for (int i=1; i <= m; i++) cout << "+";
  cout << endl;
}

void blank_space (int m)  // prints out m blank spaces
{
  for (int i=1; i <= m; i++) cout << " ";
}

void write_line (int m, int n)   /* m is column of first + in the X pattern
                                    n is side. */
{ 
  cout << "+";
  blank_space(m-2);
  cout << "+";
  blank_space(n - 2*m);
  cout << "+";
  blank_space(m-2);
  cout << "+" << endl;
}

void mid_line (int m)  // Does the middle line of the pattern.
{ 
  cout << "+";
  blank_space((m-3)/2);
  cout << "+";
  blank_space((m-3)/2);
  cout << "+" << endl;
}