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<title>Brandon Rozek</title>
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<h1>Lecture for February 13</h1>
<h2>Loops</h2>
<h3>Why Loops?</h3>
<p>While some check is true, repeat the work.</p>
<p>While the cookies aren't baked, keep baking</p>
<h3>Loop Building Process</h3>
<ol>
<li>Identify one test that must be true when the loop is finished</li>
<li>Use the <strong>opposite</strong> form of the test</li>
<li>Within loop, make <em>progress</em> towards completion of the goal.</li>
</ol>
<h3>While syntax</h3>
<pre><code class="language-java">while (expression) {
// Loop body executes if expression is true
}
// Statements execute after expression is false</code></pre>
<h3>Getting Input (Songs in a Playlist Psuedocode)</h3>
<pre><code class="language-java">// Ask user about first song
while (user says play next song) {
// play next song
// ask user about next song
}</code></pre>
<h3>Nested Loops</h3>
<p>You can have loops inside loops</p>
<pre><code class="language-java">int outer = 1;
while (outer &lt; 4) {
int inner = 1;
while (inner &lt; 4) {
System.out.println(outer + ":" + inner);
inner++;
}
outer++;
}</code></pre>
<p>This code does the following</p>
<pre><code class="language-reStructuredText">1:1
1:2
1:3
2:1
2:2
2:3
3:1
3:2
3:3</code></pre>
<h3>Break Down the Problem</h3>
<p>Never write the entire program at once! This makes it incredibly hard to debug. Instead break it into small parts.</p>
<p>Write one part -&gt; debug until it works</p>
<p>Write second part -&gt; debug until it works</p>
<p>This way you know which part of your code failed, instead of having everything fail.</p>
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