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copied!<p>I see no code where you initialise <code>a</code> to 1 so it may be it has some arbitrary value. If that arbitrary value is greater than <code>num</code>, the outer loop will never start.</p> <p>For what it's worth, I would be using <code>for</code> loops in this case since you know in advance what the limits are, something like the following pseudo-code:</p> <pre><code># Top line for i = 1 to num (inclusive): output "*" output newline # Middle lines for i = 2 to num-1: output "*" # Left char for j = 2 to num-1: # Middle chars output " " output "*" and newline # Right char # Bottom line for i = 1 to num (inclusive): output "*" output newline </code></pre> <p>Then you don't have to worry about condition checking within the loop body.</p> <p>A good rule of thumb is to use <code>for</code> for a known-before-the-start count of iterations, <code>while</code> for a loop where you don't know in advance how often you'll iterate.</p> <p>Another likely problem is your condition:</p> <pre><code>while ( num > 1 || num < 20 ) </code></pre> <p>Regardless of the value of <code>num</code>, that is always true, since you're using logical-or <code>||</code>. Think of the possibilities:</p> <pre><code>num <= 1 : false or true -> true num == 2..19 : true or true -> true num >= 20 : true or false -> true </code></pre> <p>If you want to continue looping while you have a value <em>outside</em> of the range 1..20, you should use:</p> <pre><code>while ( num < 1 || num > 20 ) </code></pre> <p>and you then end up with the following:</p> <pre><code>num < 1 : true or false -> true num == 1..20 : false or false -> false num > 20 : false or true -> true </code></pre> <hr> <p>There are quite a few other potential problems with your code, to wit:</p> <ul> <li>You appear to have the outer loop in there twice.</li> <li>You don't appear to define <code>b</code> or <code>num</code>.</li> <li>You don't appear to set <code>num</code> before the outer loop (which checks it).</li> <li>I suspect you meant to close the <code>while ( num > 1 || num < 20 )</code> loop immediately after the <code>cin.ignore()</code> call since it's meant to keep going until you get a value from 1 to 20 and <em>then</em> draw the square. As it stands, a square will be drawn even if you enter 99.</li> </ul>

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