Flowcharts for visualizing logic in Intro to Computing - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a flowchart?

A flowchart is a simple drawing that shows the steps of a process or how a decision is made. It uses shapes and arrows to explain what happens first, next, and last.

beginner

What shape is used to represent a decision in a flowchart?

A diamond shape is used to show a decision point where the answer can be yes or no, or true or false.

beginner

Why are flowcharts helpful when learning programming?

Flowcharts help by showing the order of steps and decisions clearly, making it easier to understand and plan how a program works before writing code.

beginner

What does an oval shape represent in a flowchart?

An oval shape shows the start or end of a process in a flowchart.

beginner

How do arrows function in a flowchart?

Arrows connect shapes and show the direction of the flow, telling us which step comes next.

Which shape in a flowchart shows a process or action?

A Oval

B Diamond

C Rectangle

D Circle

A rectangle represents a process or action step in a flowchart.

What does a diamond shape in a flowchart represent?

A Decision point

B Start or end

C Process

D Input/output

A diamond shape is used for decision points where yes/no or true/false choices are made.

What is the first step in a flowchart usually shown by?

A Rectangle

B Oval

C Diamond

D Arrow

An oval shape shows the start (and end) of a flowchart process.

How do arrows help in a flowchart?

A They show the flow direction

B They mark the start

C They represent decisions

D They decorate the chart

Arrows connect steps and show which step comes next.

Why use flowcharts before coding?

A To write code faster

B To decorate the program

C To avoid using computers

D To plan and understand logic clearly

Flowcharts help plan and understand the logic before writing code.

Explain how a flowchart helps visualize the logic of a simple decision-making process, like choosing what to wear based on weather.

Think about how you decide what to wear step-by-step.

Describe the main shapes used in flowcharts and what each one represents.

Remember the simple shapes and their meanings.

Practice

1. What shape is commonly used in a flowchart to represent a decision point?

easy

A. Rectangle

B. Circle

C. Oval

D. Diamond

Solution

1. Step 1: Identify flowchart shapes and their meanings

   Ovals represent start/end, rectangles represent processes, and diamonds represent decisions.

2. Step 2: Match decision point to shape

   The decision point is shown as a diamond to indicate a yes/no or true/false choice.

3. Final Answer:

   Diamond -> Option D

4. Quick Check:

   Decision = Diamond [OK]

Hint: Decisions use diamond shapes in flowcharts [OK]

Common Mistakes:

• Confusing rectangle (process) with decision
• Thinking oval is for decisions
• Using circle instead of diamond

2. Which of the following is the correct symbol to start a flowchart?

easy

A. Oval

B. Diamond

C. Rectangle

D. Parallelogram

Solution

1. Step 1: Recall flowchart start/end symbols

   Ovals are used to mark the start and end points in flowcharts.

2. Step 2: Identify the correct start symbol

   Among the options, only the oval represents the start/end point.

3. Final Answer:

   Oval -> Option A

4. Quick Check:

   Start symbol = Oval [OK]

Hint: Start and end use oval shapes in flowcharts [OK]

Common Mistakes:

• Choosing rectangle which is for processes
• Confusing diamond with start symbol
• Using parallelogram which is for input/output

3. Consider this flowchart logic: Start -> Input number -> Is number > 10? -> Yes: Print 'High' -> No: Print 'Low' -> End. What will be printed if the input is 7?

medium

A. High

B. Low

C. 7

D. Error

Solution

1. Step 1: Understand the decision condition

   The flowchart checks if the input number is greater than 10.

2. Step 2: Apply input value to condition

   Since 7 is not greater than 10, the flow follows the 'No' branch and prints 'Low'.

3. Final Answer:

   Low -> Option B

4. Quick Check:

   7 > 10? No, so print Low [OK]

Hint: Follow decision branches carefully for output [OK]

Common Mistakes:

• Printing input number instead of 'Low'
• Choosing 'High' by mistake
• Assuming error on input

4. A flowchart has a decision diamond with two arrows labeled 'True' and 'False'. The 'False' arrow mistakenly loops back to the start instead of continuing. What is the likely problem?

medium

A. Wrong shape used for decision

B. Correct flowchart with no issues

C. Infinite loop causing the process never to end

D. Missing start symbol

Solution

1. Step 1: Analyze the incorrect arrow direction

   The 'False' arrow looping back to start causes the process to repeat endlessly.

2. Step 2: Understand impact on flowchart execution

   This creates an infinite loop, preventing the flowchart from reaching an end.

3. Final Answer:

   Infinite loop causing the process never to end -> Option C

4. Quick Check:

   Loop back to start = infinite loop [OK]

Hint: Check arrow directions to avoid infinite loops [OK]

Common Mistakes:

• Thinking it's a correct flowchart
• Confusing missing start with loop issue
• Ignoring arrow labels

5. You want to design a flowchart that reads a number and prints 'Even' if the number is divisible by 2, otherwise prints 'Odd'. Which sequence of shapes correctly represents this logic?

hard

A. Oval (Start) -> Rectangle (Input) -> Diamond (number % 2 == 0?) -> Rectangle (Print 'Even') if Yes -> Rectangle (Print 'Odd') if No -> Oval (End)

B. Rectangle (Start) -> Diamond (Input) -> Oval (Check) -> Rectangle (Print) -> Oval (End)

C. Oval (Start) -> Diamond (Input) -> Rectangle (Check) -> Diamond (Print) -> Oval (End)

D. Oval (Start) -> Rectangle (Input) -> Rectangle (Check) -> Diamond (Print) -> Oval (End)

Solution

1. Step 1: Identify correct flowchart symbols for each step

   Start/end use ovals, input uses rectangle, decision uses diamond, and output uses rectangle.

2. Step 2: Match sequence to logic

   Input number (rectangle), decision if divisible by 2 (diamond), print 'Even' or 'Odd' (rectangles), then end (oval).

3. Final Answer:

   Oval (Start) -> Rectangle (Input) -> Diamond (number % 2 == 0?) -> Rectangle (Print 'Even') if Yes -> Rectangle (Print 'Odd') if No -> Oval (End) -> Option A

4. Quick Check:

   Correct shapes in logical order [OK]

Hint: Use oval-start/end, diamond-decision, rectangle-process [OK]

Common Mistakes:

• Using diamond for input or output
• Starting with rectangle instead of oval
• Mixing up decision and process shapes