Computer Science - Term one half one- ALgorithims

For next loops

A for loop is for something that has to happen for a fixed number of time for is repeat next is like do the next (e.g next count) e.g repeat FOR x(x could be anything e.g count) =1 to 10 (start to end if you have given a value to a variable can be 1 to variable) FOR x = 1 to 10 write code NEXT FOR students FOR count = 1 to students INPUT grade NEXT count Basically, you do the code inside the for loop each time for the count e.g 1-students (e.g 30) it will input grade 30 times and the next is to say after done the input grade next count again until to for loop is over

Start and end box shape

A rounded edge rectangle

Read over the sheet on who to do basic tasks (e.g Finding the Max) to check you know how to do all

Go do!

How to do a total

How to total something 1. Set the total to 0 2. Input a new value 3. Add new value to total 4. Output outside the loop total←0 FOR count = 1 to 5 INPUT newValue totaltotal+newValue NEXT count PRINT total

Else if normal

IF test (a condition (a=12)) THEN true action (i.e what happens if its true e.g PRINT a) ELSE false action (i.e what happens if its false e.g PRINT b) ENDIF

Else if two

IF test (a condition (a=12)) THEN true action (i.e what happens if its true e.g PRINT a) ELSEIF test2 THEN true action2 ELSE false action (i.e what happens if its false e.g PRINT b) ENDIF

If normal

IF test (a condition (a=12)) THEN true action (i.e what happens if its true e.g PRINT a) ENDIF

How to input data

INPUT

Practice Practice Practice

Like maths, theory is nothing!

How to tell if a number are BOTH pos/neg in an algorithm

Must input a,b before IF a mod 2 (divided by 2) = b mod 2 PRINT postive because all positive numbers can divide into 2 so there should be nothing left over if they are both positive to work out just one just do IF a mod 2 ← 0 then its positive if not its negative

n-1 decisions are needed to distinguish between

N statements e.g 2 decions are needed to distinguish between 3 statements

While loop loops

While condition (e.g a ← b) Write code (condition of while if true (can also puts if's in there)) Loop (to end it)

A process box shape (e.g stating something)

e..g x = x+1 or fill the sink rectangle

testing

e.g - for use in if's (if (testing) a ← b) a = 12 (does a =12) a<>12 Is the value of a not 12 a>= Is a greater than or equal to 12 a>=12 is a less than or equal to 12

Decison/query box

e.g is X>5 Diamond

Input/output box

e.g print X parallelogram

How to make multiple selections flow charts

first question has yes to end the other has no to the next question. Remember to go through EVERY clause not condense them into one - practice question 10

Repeat until loops

Repeat Write code Until Condition (e.g a ← b)

Repetion description

Repeatedly does something until you ask it to stop

Assignment

Saying something now = something instead of a = b its a←b (a now = b)

When declaring variables what to remember !

The variable value goes OUTSIDE the loop

Repetition in Flow charts

There is a yes or no lopp and they loop back to wither the begging of the loop or the end

Selection define

This means picking an option (e.g if this equals this SELECT this)

How to do key terms

UpperCase, bold all words capitalised bold.

How to do variables

lowerCase, noSpaces - no spaces -capital letter to indicate new word but not at begging

N decions are needed to distinguish between

n+1 statement e.g 2 decions are needed to distinguish between 3 statements

How to do 10 - 1 when you can't go backwards

num←10 (make num = 10) START FOR LOOP For x = 0-9 PRINT num-x (so its 10-0 = 10 then 10-1 = 9) NEXT END

Selection if Flow charts

question asked is placed inside a decision diamond and that the two flow lines contains arrow heads to show where to go (unlike usual) PRACTICE