Psuedo Code Pseudo Code Pseudo Fake Code Fancy computer stuff A way to organize your program before coding it General Guidelines Input Output Steps in between Not Language Specific Only you need to understand it Should not compile Steps
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A way to organize your program before coding it<br>
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General Guidelines Input
Output
Steps in between
Not Language Specific
Only you need to understand it
Should not compile<br>
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Steps to Pseudo Coding Step 1: Outline
Very General, Inputs to outputs
Little computer code used
Short and to the point
Step 2: Actual Pseudo Code
More line by line
Focus on variable storage and functions<br>
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ToolBox Variables (int, float, char, string)
Arrays, dict/hash tables
If
If-Else
While loop
For loop
Functions
The Google<br>
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Problem 1 Gregg keeps getting on your computer and running your code
Write a program that asks for the users name
If its Gregg tell him to get back to work
Input: User’s name
Output: Chiding Statement<br>
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Problem 1: Outline Solution Load in a user name from the keyboard
Check if that name is Gregg
If it is Gregg, say something<br>
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Problem 1: Pseudo Code User Name = userInput(stuff)
If User Name is Gregg
Print Chiding Statement to Snoop Gregg
Else
Print You do You!<br>
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Class Problem 1 Write a program that takes in a number from a user and tells them if it is Divisible by 11
Input = User Number
Output = Printed statement on divisibility
Hint: Mod (%) gives the remainder
5 Mod 2 = 1<br>
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Class Problem 1: Outline Solution Load in a number from the user
See if that number is divisible by 11
If it is tell them
If it is not, tell them<br>
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Class Problem 1: Pseudo Code Solution Number = userInput(stuff)
If Number Mod 11 is 0
Print Affirmative Statement
Else
Print Negative Statement<br>
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Problem 2 Write a program that takes in a number from a user and tells them if it is Divisible by 11
But keep asking until the user enters the number 0<br>
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Problem 2: Pseudo Code While(Number is not 0)
Number = userInput(stuff)
If Number Mod 11 is 0
Print Affirmative Statement
Else
Print Negative Statement Why will this not work?<br>
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Class Problem 2: Pseudo Code Number = not 0
While(Number is not 0)
Number = userInput(stuff)
If Number Mod 11 is 0
Print Affirmative Statement
Else
Print Negative Statement<br>
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Problem 3 You are given a DNA Sequence and have to report how many times the Motif CAT appears
Input = DNA Sequence (GATTACA), CAT
Output = CAT Count
Hint1: A string is really just as an array/list of characters
[‘G’,’A’,’T’,’T’,’A’,’C’,’A’]
Hint2: you can take a slice out of an array
Array[2 to 4]<br>
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Problem 3: Outline Load DNA Sequence and CAT into variables
make a motif counter
Iterate through DNA sequence
Pull out sets of three letters and compare to CAT
If we find CAT increment the counter
Report the final count<br>
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Visual Representation G A T T A C A<br>
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Problem 3: Pseudo Code Motif = CAT
DNASeq = loadFile(InputDNA)
CAT_Count = 0
For i in DNASeq Range – 2
if(DNASeq i to DNASeq i+2 is CAT)
CAT_Count + 1
Print CAT_Count<br>
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Class Problem 3 You are given a DNA sequence and have to determine its GC content (percentage)
Input = DNA sequence (GATTACA)
Output = GC content
Hint: Loops are your friend<br>
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Class Problem 3: Outline Load in sequence
Set up a GC counter
Loop through sequence
Compare every letter to G or C
Determine total nucleotide count
Do appropriate math to get percentage<br>
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Class Problem 3: Pseudo Code DNASeq = loadFile(InputDNA)
GC_Count = 0
For Letter in DNASeq
if Letter is G or C
GC_Count + 1
DNALength = length(DNASeq)
GC = GC_Count/DNALength X 100%
Print GC<br>
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Real Code<br>
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Better Real Code<br>
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Parting Lessons Inputs
Outputs
Toolbox
Take Your Time
Only you have to understand your pseudo code<br>
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Class Problem 4 You need a program that will take in a DNA sequence from a user and return the the reverse complement RNA sequence
Input: DNA sequence
Output: RNA Sequence
Hint 1: You can reverse a list, or you can loop through a list backwards
Hint2: Figuring out the complement can be done with a series of if statements<br>
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Class Problem 4: Outline Load in DNA sequence
Loop through the sequence from back to front
Check identity of each letter, add its complement to new string
Remember RNA has U, not T<br>
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Class Problem 4: Pseudo Code DNASeq = userInput(stuff)
RNASeq = empty list
Seq Length = length(DNASeq)
For I in range 0 to seq Length
Index = length(DNASeq) – I
If DNASeq[index] is G
RNASeq + C
Else if DNASeq[index] is A
RNASeq + U
… and so on<br>
