(r2) REPLAndStandardPythonProgramming < IoT_Course

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<p align="center"><font face="Liberation Sans, sans-serif"><font size="6"> *Course on Internet of Things* </font></font></p>
---+ Exercises Session 1:
---++ Introductory remarks:

The scripts we are going to develop during these exercises do not depend on any system issues: We do not use command line arguments not available in !MicroPython nor do we use any hardware specific features which are not available on a PC. The exercises can therefore be developed and run on the ESP32 but also on any standard PC with Python3 installed.
---++ Exercise 1:

Connect to your ESP32 with minicom or thonny.

Using REPL:
   * <p>print “Hello World!”</p>
   * <p>read in a text using <i>input() </i>and print it</p>
   * <p>Calculate</p> <p><img align="middle" alt="calculations.png" height="52" src="%PUBURL%/UCC_Course_2020/Exercises/calculations.png" title="calculations.png" width="142" /></p>
   * <p>Calculate sin(30°) <br /> If you see errors, how do you correct them? Are the results correct?</p>
---++ Exercise 2:

Write a script that assigns the values 5 and 3 to the variables a and b respectively

Print the results of 4 basic arithmetic operations:
   * <p>a+b</p>
   * <p>a-b</p>
   * <p>a*b</p>
   * <p>a/b</p>
Which result do you observe for division? Can you correct?

Improve this program asking the user to enter 2 real numbers (floats) separated by a space. This is how it should look like:

<img alt="calcOk.png" height="172" src="%ATTACHURL%/calcOk.png" title="calcOk.png" width="845" />

If this happens:

<img alt="conversionError.png" height="150" src="%ATTACHURL%/conversionError.png" title="conversionError.png" width="636" />

when the user mistypes and enters something that is not an integer, can you capture the error and simply ask the user to repeat his input, until you get 2 correct integer numbers?

*Bonus points:* Writing a parser for user input is rather easy if the numbers and operator are separated by spaces (have a look at the split method of strings). It is quite a bit more tricky if you allow entering calculations without spaces between the operands and the operator. Can you write a parser accomplishing this?

Try your parser on this input:

5.3+4.7      ok<br />5.3++4.7    not ok<br />5..3 + 4.7   not ok<br />.3+.7          ok<br />5.3+4b7      not ok
---++ Exercise 3:

Like in exercise2, start with 2 number a,b with values 5 and 3. In your program check which of the 2 numbers is bigger and print the result. Then ask the user for 2 integer numbers. Make sure he enters 2 correct numbers and capture possible errors. This is a typical output:

<img alt="conditions.png" height="188" src="%ATTACHURL%/conditions.png" title="conditions.png" width="649" />

-- %USERSIG{UliRaich - 2020-05-03}%

---++ Comments

%COMMENT%

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
png	calcOk.png	r1	manage	21.7 K	2020-05-03 - 19:52	UliRaich
png	conditions.png	r1	manage	28.8 K	2020-05-03 - 20:25	UliRaich
png	conversionError.png	r1	manage	19.3 K	2020-05-03 - 19:42	UliRaich

Topic revision: r2 - 2020-05-03 - UliRaich