The first three phases of programming problem solving were reviewed.
step 1 Understand what the problem is. Absorb its language
and become familiar with its terms and its data and
output.
Ask: What is given? What is the data?
Ask: What is the goal? What would the output look like?
The focus in on WHAT.
Emphacize WHAT has to be done and
---- suppress concern with HOW to do it.
---
SAE = Suppress And Emphacize
HOW WHAT
step 2 Develop a top-level plan, a step by step algorithm to
solve the problem you a fairly deep understanding of
from step 1 efforts.
Before going on to step 3, develop another possible
approach to solving the problem. Develop at least a 2nd
approach. Restate your 1st plan to improve it. Do these
two differently stated algorithms suggest a 3rd.
CHOOSE the better algorithm.
This is the PLAN of HOW to do it.
HOW to get from the GIVEN (Input)
to the GOAL (output)
Before going on to step 3 with your chosen plan (algorithm),
ask:
a. is this plan simple enough to comprehend and work
with. ------
b. does this plan capture the whole problem, is this
plan adequate, does it solve the problem as stated?
--------
Criteria: Is it a simple and an adequate plan?
Step 3: Translate the step 2 plan into the programming language
of your choice. Code it in Fortran or Pascal or C or LOGO.
Code it - after heeding the proverb:
RESIST THE URGE TO CODE
------ --- ---- -- ----
def binary( theValue ): # Function header line has focus on WHAT it does.
b = "" # All the rest of the function suite (function body)
while theValue > 0: # are separate and deal with
b = str( theValue % 2 ) + b # the HOW to get from theValue
theValue = theValue // 2 # numeric input to the binary
# string representation output.
return b
---------------------------------------------------------------------------
# Tuesday, Oct 27, 2015 - Obtaining the BINARY string by a different algorithm
def binary( theValue ): # The function header line here has focus on WHAT
divisor = 1 # find the largest power of two <= theValue
while divisor * 2 <= theValue:
divisor = divisor * 2
b = "" # obtains the most significant digit FIRST
while theValue > 0: # ----------------------------
b = b + str( theValue // divisor )
theValue = theValue % divisor
divisor = divisor // 2 # divisor for theValue of 88 is:
# 64, then 32, then 16, then 4,
return b # then 2 and finally 1.
num = 193
print( binary(num), num )
num = 225
print( binary(num), num )
Start with 256 for all numbers >= 256 and < 512. Divisor 256. Start with 128 for all numbers >= 128 and < 256. Divisor 128 Start with 64 for all numbers >= 64 and < 128. Divisor 64 ... Start with 16 for any number between 16 and 31. Divisor 16
PDF of Powerpoint for Python FUNCTIONS with some Files practice questions and review.
Review the Day #17 Penny Math and Dollar Words and files original example.