Project Solution: Hollow Square Pattern

Solution: HollowSquare.java

<span class="pln">
</span><span class="kwd">import</span><span class="pln"> java</span><span class="pun">.</span><span class="pln">util</span><span class="pun">.</span><span class="typ">Scanner</span><span class="pun">;</span><span class="pln">

</span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">class</span><span class="pln"> </span><span class="typ">HollowSquare</span><span class="pln"> </span><span class="pun">{</span><span class="pln">

    </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">static</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> main</span><span class="pun">(</span><span class="typ">String</span><span class="pun">[]</span><span class="pln"> args</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
        </span><span class="typ">Scanner</span><span class="pln"> scanner </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Scanner</span><span class="pun">(</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">in</span><span class="pun">);</span><span class="pln">
        </span><span class="kwd">int</span><span class="pln"> n</span><span class="pun">;</span><span class="pln">

        </span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="str">"Enter the number of rows: "</span><span class="pun">);</span><span class="pln">
        n </span><span class="pun">=</span><span class="pln"> scanner</span><span class="pun">.</span><span class="pln">nextInt</span><span class="pun">();</span><span class="pln">

        </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> i </span><span class="pun">=</span><span class="pln"> n</span><span class="pun">;</span><span class="pln"> i </span><span class="pun">&gt;=</span><span class="pln"> </span><span class="lit">1</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">--)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
            </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> j </span><span class="pun">=</span><span class="pln"> </span><span class="lit">1</span><span class="pun">;</span><span class="pln"> j </span><span class="pun">&lt;=</span><span class="pln"> i </span><span class="pun">-</span><span class="pln"> </span><span class="lit">1</span><span class="pun">;</span><span class="pln"> j</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
                </span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="str">" "</span><span class="pun">);</span><span class="pln">
            </span><span class="pun">}</span><span class="pln">

            </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> k </span><span class="pun">=</span><span class="pln"> </span><span class="lit">1</span><span class="pun">;</span><span class="pln"> k </span><span class="pun">&lt;=</span><span class="pln"> n</span><span class="pun">;</span><span class="pln"> k</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
                </span><span class="kwd">if</span><span class="pln"> </span><span class="pun">(</span><span class="pln">i </span><span class="pun">==</span><span class="pln"> n </span><span class="pun">||</span><span class="pln"> i </span><span class="pun">==</span><span class="pln"> </span><span class="lit">1</span><span class="pln"> </span><span class="pun">||</span><span class="pln"> k </span><span class="pun">==</span><span class="pln"> </span><span class="lit">1</span><span class="pln"> </span><span class="pun">||</span><span class="pln"> k </span><span class="pun">==</span><span class="pln"> n</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
                    </span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="str">"*"</span><span class="pun">);</span><span class="pln">
                </span><span class="pun">}</span><span class="pln"> </span><span class="kwd">else</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
                    </span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="str">" "</span><span class="pun">);</span><span class="pln">
                </span><span class="pun">}</span><span class="pln">
            </span><span class="pun">}</span><span class="pln">

            </span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">();</span><span class="pln">
        </span><span class="pun">}</span><span class="pln">

        scanner</span><span class="pun">.</span><span class="pln">close</span><span class="pun">();</span><span class="pln">
    </span><span class="pun">}</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span>

<span class="pln">
</span><span class="typ">Enter</span><span class="pln"> the number </span><span class="kwd">of</span><span class="pln"> rows</span><span class="pun">:</span><span class="pln"> </span><span class="lit">5</span><span class="pln">
    </span><span class="pun">*****</span><span class="pln">
   </span><span class="pun">*</span><span class="pln">   </span><span class="pun">*</span><span class="pln">
  </span><span class="pun">*</span><span class="pln">   </span><span class="pun">*</span><span class="pln">
 </span><span class="pun">*</span><span class="pln">   </span><span class="pun">*</span><span class="pln">
</span><span class="pun">*****</span>

inside star

<span class="pln">
</span><span class="kwd">import</span><span class="pln"> java</span><span class="pun">.</span><span class="pln">util</span><span class="pun">.</span><span class="typ">Scanner</span><span class="pun">;</span><span class="pln">

</span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">class</span><span class="pln"> </span><span class="typ">HollowSquare</span><span class="pln"> </span><span class="pun">{</span><span class="pln">

    </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">static</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> main</span><span class="pun">(</span><span class="typ">String</span><span class="pun">[]</span><span class="pln"> args</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
        </span><span class="typ">Scanner</span><span class="pln"> scanner </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Scanner</span><span class="pun">(</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">in</span><span class="pun">);</span><span class="pln">
        </span><span class="kwd">int</span><span class="pln"> n</span><span class="pun">;</span><span class="pln">

        </span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="str">"Enter the number of rows: "</span><span class="pun">);</span><span class="pln">
        n </span><span class="pun">=</span><span class="pln"> scanner</span><span class="pun">.</span><span class="pln">nextInt</span><span class="pun">();</span><span class="pln">

        </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> i</span><span class="pun">=</span><span class="pln">n</span><span class="pun">;</span><span class="pln">i</span><span class="pun">&gt;=</span><span class="lit">1</span><span class="pun">;</span><span class="pln">i</span><span class="pun">--)</span><span class="pln">
		</span><span class="pun">{</span><span class="pln">
			</span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> j</span><span class="pun">=</span><span class="lit">1</span><span class="pun">;</span><span class="pln">j</span><span class="pun">&lt;=</span><span class="pln">i</span><span class="pun">-</span><span class="lit">1</span><span class="pun">;</span><span class="pln">j</span><span class="pun">++)</span><span class="pln">
			</span><span class="pun">{</span><span class="pln">
		 		</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="str">" "</span><span class="pun">);</span><span class="pln">
			</span><span class="pun">}</span><span class="pln">

			</span><span class="kwd">for</span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> k</span><span class="pun">=</span><span class="lit">1</span><span class="pun">;</span><span class="pln">k</span><span class="pun">&lt;=</span><span class="pln">n</span><span class="pun">;</span><span class="pln">k</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
				</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="str">"*"</span><span class="pun">);</span><span class="pln">
			</span><span class="pun">}</span><span class="pln">

		 </span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="str">"\n"</span><span class="pun">);</span><span class="pln">

		</span><span class="pun">}</span><span class="pln">
    </span><span class="pun">}</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span>

Output:

<span class="pln">
</span><span class="typ">Enter</span><span class="pln"> the number </span><span class="kwd">of</span><span class="pln"> rows</span><span class="pun">:</span><span class="pln"> </span><span class="lit">5</span><span class="pln">
    </span><span class="pun">*****</span><span class="pln">
   </span><span class="pun">*****</span><span class="pln">
  </span><span class="pun">*****</span><span class="pln">
 </span><span class="pun">*****</span><span class="pln">
</span><span class="pun">*****</span>