/* triangle.cpp -- Matt Mahoney, mmahoney@cs.fit.edu

ANALYSIS (required for homework assignments)

This program prompts the user to enter his/her name and prints a
greeting, "Hello, name!" surrounded by a triangle of asterisks.
The greeting is on the third line from the bottom, with one space
on the left and one or two spaces on the right.  For instance:

  Please enter your name: Matt
            *
           * *
          *   *
         *     *
        *       *
       *         *
      *           *
     *             *
    * Hello, Matt!  *
   *                 *
  *********************

DESIGN (optional, recommended for large projects)

To solve this problem, let us number the n lines of the triangle
0, 1, 2, ... n - 1.  The greeting is on line n - 3.  Line n - 1
consists of 2n - 1 asterisks with no leading spaces.  Line 0
consists of a single asterisk with n - 1 leading spaces.  For all
other lines, line i has n - i - 1 leading spaces, a *, then 2i - 1
spaces, then another *.  The number of spaces is odd, so on line n - 3
where we substitute the greeting, its length must also be odd, so we
pad it with an extra space if necessary.

We solve the problem with a loop going from 0 to n - 1 for each line,
and, testing for the special cases of lines 0 (the top),
n - 3 (the greeting), and n - 1 (the bottom).

TESTING (required)

Tested under SunOS 5.8 on evans.cs.fit.edu with g++ 2.95.1
and Windows Me, DJGPP 2.95.2

To compile: g++ triangle.cpp
*/

#include <iostream>
#include <string>
using namespace std;

int main() {

  // Prompt for the user's name and construct a greeting with length odd.
  cout << "Please enter your name: ";
  string name;
  cin >> name;
  string greeting = "Hello, " + name + "!";
  if (greeting.size()%2 == 0)  // even?
    greeting += " ";

  // Print the triangle.
  const int n=greeting.size()/2 + 5;  // Height of the triangle
  for (int i=0; i<n; ++i) {
    if (i == 0)
      cout << string(n-1, ' ') << "*\n";  // top
    else if (i == n-1)
      cout << string(n*2-1, '*') << endl;  // bottom
    else if (i == n-3)
      cout << "  * " << greeting << " *\n";  // greeting
    else
      cout << string(n-i-1, ' ') << "*" << string(2*i-1, ' ') << "*\n";
  }
  return 0;
}