PROGRAMMINGIn

Lesson 5

RECAP

Complete the starter activity

OBJECTIVES Understand how to use looping statement (while) Understand to use the break statement Understand the development process of flow charts to

comments to code

OUTCOMES All-Level 4 written code using while - with help

developed programs using pseudo code

Most-Level 5 Be able to write a these with little help.

Some-Level 6 Independently write these and adapt them and complete the extension tasks.

LOOPS

You might remember this code from your truth table of last lesson. It is part of the function that got the user input.

It uses a while statement to keep asking the user to input a value until it is one of the required values.

WHILE STATEMENT

while expression : statement 1 statement 2 statement 3

Statements are executed while the expression is true

Notice the indentation – this defines

the statements that are in the while statement

Don’t forget the full colon

WRITE A LOOPY PROGRAM – PSEUDO CODE

Write a program that asks the user for a number and counts down to 1 displaying each number as it goes.

a=int(a) – converts number a to an integer

You have the rest of the knowledge.

Extension:Get you program to calculate the factorial of the number.

Hint: factorial of 4 is 4 * 3 * 2 * 1.

start

Ask user for a number

Convert to integer

Display number

Subtract one

Is number > 0

Yes

endNo

• Write the pseudo code for the program.

• We will then write the program comments from this pseudo code

• We will then fill in the code for each comment.

end

WRITE A LOOPY PROGRAM - COMMENTS

Is number > 0

start

Ask user for a number

Convert to integer

Display number

Subtract one

Yes

No

WRITE A LOOPY PROGRAM - CODE

Extension:Get you program to calculate the factorial of the number. Hint: factorial of 4 is 4 * 3 * 2 * 1.

With your classmate you have 2 mins to discuss…

What was most difficult in the program

What was most fun

What was the boring part

CLASS DISCUSSION

WHILE STATEMENT BREAK

while expression : statement 1 statement 2

breakThis command quits from the while statement – even

if the expression is still true.

Statements are executed while the expression is true

Notice the indentation – this defines

which statements are in the

while statement

GUESS THE NUMBER – VERSION 2 Remember this – guessing a random number….

I want you to make it even better

Give the user 6 chances to guess the number - use while statement

Let them know if their guess is too high - if statement

Let them know if their guess is too low - if statement

GUESS THE NUMBER – VERSION 2

WHAT DO WE NEED TO CHANGE

Set guesses to zero

Exit from while loop

Add 1 to guesses

User has a guess

No

NoGuess

= numbe

r

Yes

NoGuess

> numbe

r

Tell user too highYes

Tell user too low

Guess <

number

Yes

Guesses > 6No

Yes Exit from while loop

You have previously written most of this program.

All you need to do is write the new section

Set guesses to zero

Exit from while loop

Add 1 to guesses

User has a guess

No

No

Guess =

number

Yes

NoGuess >

number

Tell user too high

Yes

Tell user too low

Guess <

number

Yes

Guesses > 6

No

Yes Exit from while loop

WRITE THE CODE

EXTENSIONS

Make the random number range from 1 to 30

Let them know the random number if they fail to guess it.

PLENARY

Complete the Lesson 5 plenary Quiz