Ch 1: Algorithms and Flowcharts Class 9 AI Python Notes
Ch 1: Algorithms and Flowcharts Class 9 AI Python Notes
Introduction
Every machine follows a particular path of action. It goes through specific steps to accomplish the given task. For example, a microwave can warm food for us and does not perform any other functions because it is explicitly designed for this task, a washing machine can wash clothes for us and not do anything else.
What is an Algorithm?
A logical step-by-step method to solve the problem is called algorithm, in other words, an algorithm is a procedure for solving problems. Algorithms can be presented by natural languages, pseudo code and flowcharts, etc. for example
1. Algorithm to make an instant noodles
Steps are:
1. Take a pan and boil approx. 200 ml of water.
2. Add noodles and tastemaker to the boiling water.
3. Stir constantly and cook in the open pan till the water is soaked by the noodles.
4. Serve Hot
2. Algorithm to make an Tea
Steps are:
1. Take a pan and boil water.
2. Add tea leaves
3. Add milk, sugar according to your taste.
4. Filter it and serve
NOTE: There may be other ways to make instant noodles and Tea
What is a flowchart?
Flowchart is the graphical or pictorial representation of an algorithm with the help of different symbols, shapes and arrows. Various symbols used in flowchart are:

Q1. Write an algorithm to print numbers from 1 to 20. Also draw the flowchart.
ALGORITHM
1. Initialize X as 0,
2. Increment X by 1
3. Print X
4. If X is less than 20 then go back to step 2.
FLOWCHART

Q2. Write an algorithm and draw flowchart to convert Temperature from Fahrenheit (℉) to Celsius (℃)
Algorithm
Step 1: Read temperature in Fahrenheit
Step 2: Calculate temperature with formula C=5/9*(F-32)
Step 3: Print C
Flow Chart

Q3. Write an algorithm and draw flowchart to check whether a number is prime or not.
STEP 1: Start
STEP 2: Read num
STEP 3: Set i = 2
STEP 4: Repeat steps 5 and 6 until i < num
STEP 5: [Check whether num is divisible or not]
if num % i == 0 then
Goto step 7
Else
Goto step 6
STEP 6: Set i = i + 1
STEP 7: if i == num then
Print "Number is Prime"
Else
Print "Number is not Prime"
STEP 8: Stop

Q4. Write an algorithm on how does a traffic signal work?
ALGORITHM:
Step 1: Start
Step 2: Initialize signal to Green
Step 3: Display Green light for a specified time duration (e.g., 60 seconds)
Step 4: Change signal to Yellow
Step 5: Display Yellow light for a short duration (e.g., 5 seconds)
Step 6: Change signal to Red
Step 7: Display Red light for a specified duration (e.g., 55 seconds)
Step 8: Repeat from step 2
Q5. Write an algorithm to add two numbers.
Ans.
Step 1: Start
Step 2: Read the first number (say n1)
Step 3: Read the second number (say n2)
Step 4: Calculate the sum of n1 and n2
Step 5: S = n1 + n2
Step 6: Display the result (S)
Step 7: End
Q6. Write an algorithm to find average of two numbers.
Ans.
Step 1: Start
Step 2: Read the first number (say num1)
Step 3: Read the second number (say num2)
Step 4: Calculate the average of num1 and num2
Step 5: avrg = (num1 + num2)/2
Step 6: Display the result (avrg)
Step 7: End
Q7. Draw a flow chart to show the area and perimeter of rectangle.

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