Flowcharts for visualizing logic in Intro to Computing - Draw & Build Visually

Draw This - beginner

Draw a flowchart to check if a number is positive, negative, or zero. Use the number 7 as input.

5 minutes

Hint 1

Hint 2

Hint 3

Hint 4

Hint 5

Grading Criteria

Start and End symbols present

Input step included

Decision diamonds used for comparisons

Correct branching for >0, <0, and =0 cases

Outputs labeled correctly as "Pos", "Neg", or "Zero"

Arrows correctly connect all steps without breaks

Solution

  _______
 / Start \
 \_______/
     |
     v
  _____________
 | Input number |
 |     (7)      |
  -------------
     |
     v
  ______________________
 | Is number > 0? (7>0) |
  ----------------------
    /          \
  Yes           No
  /              \
 v                v
 _______       ______________________
|Print  |     | Is number < 0? (7<0) |
|"Pos"  |      ----------------------
|_______|       /          \
    |         Yes           No
    |          /             \
    v         v               v
  _______  _______        _______
 | End  | |Print |      |Print  |
 |      | |"Neg" |      |"Zero" |
 |______| |_______|      |_______|
             |              |
             v              v
           _______        _______
          | End  |      | End  |
          |      |      |      |
          |______|      |______|

1. Start the flowchart with a Start symbol.

2. Input the number (7 in this case).

3. Check if the number is greater than zero using a decision diamond.

4. If yes, print "Pos" and end.

5. If no, check if the number is less than zero.

6. If yes, print "Neg" and end.

7. If no, it means the number is zero, so print "Zero" and end.

This flowchart clearly shows the logic to classify a number as positive, negative, or zero.

Variations - 2 Challenges

[beginner] Draw a flowchart to check if a number is even or odd. Use the number 12 as input.

[intermediate] Draw a flowchart to find the largest of three numbers: A=15, B=23, C=8.

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