Exploring Algorithms

Tiffany White,Thu Jun 22 2017

For example, if I want to make a recipe for stuffed peppers, I would usually follow steps such as:

This is a really simple example of an algorithm.

https://www.youtube.com/embed/XSLj46Lfpfk (opens in a new tab)

Here, we step through getting the data with a few conditionals:

   <span class="&quot;c1&quot;">// declare and assign values to variables that we can use later</span>
	<span class="&quot;n&quot;">String</span> <span class="&quot;n&quot;">firstName</span><span class="&quot;o&quot;">=</span><span class="&quot;s&quot;">"N/A"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">lastName</span><span class="&quot;o&quot;">=</span><span class="&quot;s&quot;">"N/A"</span><span class="&quot;o&quot;">;</span>
	<span class="&quot;kt&quot;">int</span> <span class="&quot;n&quot;">age</span><span class="&quot;o&quot;">=</span><span class="&quot;mi&quot;">0</span><span class="&quot;o&quot;">,</span> <span class="&quot;n&quot;">speedLimit</span><span class="&quot;o&quot;">=</span><span class="&quot;mi&quot;">0</span><span class="&quot;o&quot;">,</span> <span class="&quot;n&quot;">actualSpeed</span><span class="&quot;o&quot;">=</span><span class="&quot;mi&quot;">0</span><span class="&quot;o&quot;">,</span> <span class="&quot;n&quot;">mphOverLimit</span><span class="&quot;o&quot;">=</span><span class="&quot;mi&quot;">0</span><span class="&quot;o&quot;">;</span>
	<span class="&quot;kt&quot;">int</span> <span class="&quot;n&quot;">baseFine</span><span class="&quot;o&quot;">=</span><span class="&quot;mi&quot;">0</span><span class="&quot;o&quot;">,</span> <span class="&quot;n&quot;">underAgeFine</span><span class="&quot;o&quot;">=</span><span class="&quot;mi&quot;">0</span><span class="&quot;o&quot;">,</span> <span class="&quot;n&quot;">zoneFine</span><span class="&quot;o&quot;">=</span><span class="&quot;mi&quot;">0</span><span class="&quot;o&quot;">,</span> <span class="&quot;n&quot;">totalFine</span><span class="&quot;o&quot;">=</span><span class="&quot;mi&quot;">0</span><span class="&quot;o&quot;">;</span>

//################ Input ###################### // Here, the person calculating the fine would enter the data which is // read in by the scanner object System.out.println("Enter your first name and last name. > "); firstName = kbd.next(); lastName = kbd.next(); System.out.println("Enter your age. > "); age = kbd.nextInt(); System.out.println("Enter the speed limit. > "); speedLimit = kbd.nextInt(); System.out.println("Enter your actual speed. > "); actualSpeed = kbd.nextInt(); System.out.println("Did the violation occur in a construction zone? Enter yes or no. > "); String inConstructionZone = kbd.next();

//########### Speed Limit Fines ######### // Algorithm, step by step, giving the computer instructions on how to calculate // the fine using conditionals if (actualSpeed > speedLimit) { mphOverLimit = actualSpeed - speedLimit; } else { mphOverLimit = 0; } if (mphOverLimit < 5) { baseFine = 0; } else if (mphOverLimit <= 20) { baseFine = mphOverLimit / 5 30; } else if (mphOverLimit > 20) { baseFine = mphOverLimit / 5 50; }

 <span class="&quot;c1&quot;">//########### Zone Fines ############</span>

if (mphOverLimit < 5) { zoneFine = 0; } else if (inConstructionZone.equals("yes") || inConstructionZone.equals("y") || inConstructionZone.equals("Yes") || inConstructionZone.equals("YES")) { zoneFine = baseFine * baseFine; } else if (inConstructionZone.equals("no") || inConstructionZone.equals("n") || inConstructionZone.equals("No") || inConstructionZone.equals("NO")) { zoneFine = 0; }

 <span class="&quot;c1&quot;">//############## Age Fines #############</span>

 <span class="&quot;k&quot;">if</span> <span class="&quot;o&quot;">(</span><span class="&quot;n&quot;">age</span> <span class="&quot;o&quot;">&lt;</span> <span class="&quot;mi&quot;">21</span> <span class="&quot;o&quot;">&amp;&amp;</span> <span class="&quot;n&quot;">mphOverLimit</span> <span class="&quot;o&quot;">&gt;</span> <span class="&quot;mi&quot;">20</span><span class="&quot;o&quot;">)</span>
 <span class="&quot;o&quot;">{</span>
	 <span class="&quot;n&quot;">underAgeFine</span> <span class="&quot;o&quot;">=</span> <span class="&quot;mi&quot;">300</span><span class="&quot;o&quot;">;</span>
 <span class="&quot;o&quot;">}</span>
 <span class="&quot;k&quot;">else</span>
 <span class="&quot;o&quot;">{</span>
	 <span class="&quot;n&quot;">underAgeFine</span> <span class="&quot;o&quot;">=</span> <span class="&quot;mi&quot;">0</span><span class="&quot;o&quot;">;</span>
 <span class="&quot;o&quot;">}</span>

//############# Total Charges ##############

 <span class="&quot;n&quot;">totalFine</span> <span class="&quot;o&quot;">=</span> <span class="&quot;n&quot;">baseFine</span> <span class="&quot;o&quot;">+</span> <span class="&quot;n&quot;">zoneFine</span> <span class="&quot;o&quot;">+</span> <span class="&quot;n&quot;">underAgeFine</span><span class="&quot;o&quot;">;</span>
   <span class="&quot;c1&quot;">// Telling the JVM to print out each formatted scanner input on a new line</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">println</span><span class="&quot;o&quot;">();</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">format</span><span class="&quot;o&quot;">(</span> <span class="&quot;s&quot;">"name: %s, %sn"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">lastName</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">firstName</span> <span class="&quot;o&quot;">);</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">format</span><span class="&quot;o&quot;">(</span> <span class="&quot;s&quot;">"age: %d yrs.n"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">age</span> <span class="&quot;o&quot;">);</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">format</span><span class="&quot;o&quot;">(</span> <span class="&quot;s&quot;">"actual speed: %d mph.n"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">actualSpeed</span> <span class="&quot;o&quot;">);</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">format</span><span class="&quot;o&quot;">(</span> <span class="&quot;s&quot;">"speed limit: %d mph.n"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">speedLimit</span> <span class="&quot;o&quot;">);</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">format</span><span class="&quot;o&quot;">(</span> <span class="&quot;s&quot;">"mph over limit: %d mph.n"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">mphOverLimit</span> <span class="&quot;o&quot;">);</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">format</span><span class="&quot;o&quot;">(</span> <span class="&quot;s&quot;">"base fine: $%dn"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">baseFine</span> <span class="&quot;o&quot;">);</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">format</span><span class="&quot;o&quot;">(</span> <span class="&quot;s&quot;">"zone fine: $%dn"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">zoneFine</span> <span class="&quot;o&quot;">);</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">format</span><span class="&quot;o&quot;">(</span> <span class="&quot;s&quot;">"under age fine: $%dn"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">underAgeFine</span> <span class="&quot;o&quot;">);</span>
	<span class="&quot;n&quot;">System</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">out</span><span class="&quot;o&quot;">.</span><span class="&quot;na&quot;">format</span><span class="&quot;o&quot;">(</span> <span class="&quot;s&quot;">"total fine: $%dn"</span><span class="&quot;o&quot;">,</span><span class="&quot;n&quot;">totalFine</span> <span class="&quot;o&quot;">);</span>
<span class="&quot;o&quot;">}</span> <span class="&quot;c1&quot;">// END MAIN</span>

} // END CLASS

For example, the Bubble Sort algorithm sorts the values in an array from smallest to largest by assessing the first index and comparing it with the next. If the first value is larger than the second, the bubble sort algorithm swaps the two values.

Here is a version of the bubble sort algorithm in pseudocode:

loop = list.count;

for i = 0 to loop-1 do: swapped = false

  </span><span class="&quot;k&quot;">for </span>j <span class="&quot;o&quot;">=</span> 0 to loop-1 <span class="&quot;k&quot;">do</span>:

     // compare the adjacent elements
     <span class="&quot;k&quot;">if </span>list[j] &gt; list[j+1] <span class="&quot;k&quot;">then</span>
        // swap them
        swap<span class="&quot;o&quot;">(</span> list[j], list[j+1] <span class="&quot;o&quot;">)</span>
        swapped <span class="&quot;o&quot;">=</span> <span class="&quot;nb&quot;">true
     </span>end <span class="&quot;k&quot;">if

  </span>end <span class="&quot;k&quot;">for</span>

  // <span class="&quot;k&quot;">if </span>no number was swapped that means
  // array is sorted now, <span class="&quot;nb&quot;">break </span>the loop

  <span class="&quot;k&quot;">if</span><span class="&quot;o&quot;">(</span>not swapped<span class="&quot;o&quot;">)</span> <span class="&quot;k&quot;">then
     </span><span class="&quot;nb&quot;">break
  </span>end <span class="&quot;k&quot;">if

end for

end procedure return list

To see the implementation in java: