Creating Flowcharts Principles of Engineering © 2012 Project Lead The Way, Inc.

Name of PowerPoint CIM Name of Lesson Definition A flowchart is a schematic representation of an algorithm or a process. A schematic is a diagram that uses special symbols in place of actual pictures. In a wiring schematic, for example, a squiggly line is used to represent a resistor. An algorithm is a series of steps that tell how to complete a task. For example, an algorithm for reducing a mathematical expression could be: First, perform the operations contained within the parentheses. Then calculate the exponent, if preset. Next, multiply and divide from left to right. Finally, add and subtract from left to right. Here we have a simple flowchart that might show the steps required to feed a dog. Project Lead The Way, Inc. Copyright 2008

Parts of a Flowchart Start/end Input/output Process Arrows Display Name of PowerPoint CIM Name of Lesson Parts of a Flowchart Start/end Input/output Process Arrows Display Decision Project Lead The Way, Inc. Copyright 2008

Start/End Shape is a rounded rectangle Name of PowerPoint CIM Name of Lesson Start/End Shape is a rounded rectangle Start is required of all flow charts Some flow charts may not have an END The design process is iterative; that is, it may repeat steps, or it may backtrack several steps. Project Lead The Way, Inc. Copyright 2008

Process Shape is rectangular Name of PowerPoint CIM Name of Lesson Process Shape is rectangular Process involves the action or the verb part of the flowchart Examples include Add 1 Turn the motor on Turn the light off Rotate the part Project Lead The Way, Inc. Copyright 2008

Input/Output Shape is a parallelogram Name of PowerPoint CIM Name of Lesson Input/Output Shape is a parallelogram Indicates that manual operation is needed Examples include Type in the weight Check the balance Time the operation Project Lead The Way, Inc. Copyright 2008

Decision Shape is a rhombus Outcome is either yes or no Name of PowerPoint CIM Name of Lesson Decision Shape is a rhombus Outcome is either yes or no Examples include Is this number larger than 10? Does the weight meet specifications? Has the count been reached? From geometry you may remember that a rhombus is a quadrilateral with all four sides congruent. It is different from a square in that the angles are not all right angles. Some refer to this block as a diamond because it has been rotated 45o, whereas most rhombi lie on their bases. Project Lead The Way, Inc. Copyright 2008

Arrows Arrows indicate the flow of the chart. Name of PowerPoint CIM Name of Lesson Arrows Arrows indicate the flow of the chart. Arrows are drawn from the output of one block to the input of another. Only one arrow can represent outputs. Multiple arrows may represent inputs. Project Lead The Way, Inc. Copyright 2008

Example Flowchart COUNT... Count from 1 to 9 by odd numbers. Name of PowerPoint CIM Name of Lesson Example Flowchart Count from 1 to 9 by odd numbers. Before attempting to draw the flowchart, determine what you want the output to be. What is the first block (always)? Answers on next slide. COUNT... Project Lead The Way, Inc. Copyright 2008

Name of PowerPoint CIM Name of Lesson Step 1 The output will be 1, 3, 5, 7, 9. The Start block is always first. START Project Lead The Way, Inc. Copyright 2008

Step 2 The program begins with the number 1. START INPUT 1 Name of PowerPoint CIM Name of Lesson Step 2 The program begins with the number 1. START INPUT 1 Project Lead The Way, Inc. Copyright 2008

Step 3 Now that there is a number, the program will state the number. Name of PowerPoint CIM Name of Lesson Step 3 Now that there is a number, the program will state the number. START INPUT 1 SAY NUMBER Project Lead The Way, Inc. Copyright 2008

Name of PowerPoint CIM Name of Lesson Step 4 The number 2 will be added to 1 so that the program will continue to count by odd numbers. START INPUT 1 SAY NUMBER To move from 1 to 3, we would add 2. This is a crucial step because it determines the pattern for the rest of the process. ADD 2 Project Lead The Way, Inc. Copyright 2008

Name of PowerPoint CIM Name of Lesson Step 5 START INPUT 1 SAY NUMBER Add a decision block so that the program will continue counting until the value is greater than 9. ADD 2 Is number >9? NO Project Lead The Way, Inc. Copyright 2008

Step 6 Once the number is greater than 9, the program ends. START END Name of PowerPoint CIM Name of Lesson Step 6 START INPUT 1 SAY NUMBER Once the number is greater than 9, the program ends. ADD 2 Is number >9? NO If yes, the flow chart will stop. If no, it will flow back to the arrow above, which is Add 2. Does it matter which branch we call Yes and which one we call No? (Yes, for the flow.) If it does matter, can we make it work? (Yes, we can make it work either way.) What would the flow chart look like? (Either switch the places for Yes and No on the Decision block and change where the arrows lead, OR simply switch where the arrows lead. Sometimes this second choice is not a good one, even though it sounds easier, because it makes the flow chart look sloppy. In this example the END block is right below Yes. If END matches up with No, the flowchart would look messy.) YES END Project Lead The Way, Inc. Copyright 2008

Your Turn Create a flow chart that shows how to pour a glass of milk. Name of PowerPoint CIM Name of Lesson Your Turn Create a flow chart that shows how to pour a glass of milk. How is this problem different from the one before it? (This problem has many solutions.) Does it matter what your “Start” represents? (Yes, it will determine how you proceed. Your Start may require a check to see if you even have any milk, or it may begin with a direction to go to the store to buy milk.) What sort of assumptions do you make when you create a flowchart like this one? (You must decide where to start and how far you want to take it. Does the glass size matter? Does it matter where the person using the flowchart is standing when beginning? Do you want the end to come when the milk is poured, put away, or when the glass is washed?) Project Lead The Way, Inc. Copyright 2008