Lecture 1

Question 1

Why give names to values in expressions?

Answer 1

1. Reuse names instead of values (imagine having to repeat a flot with 12 digits every time I want to re-use it)
2. Make code easier to read and modify

Question 2

How are expressions evaluated in Python?

Question 3

What are the values of meters and feet variables after each line is executed?
~~~
meters = 100
feet = 3.2808 * meters
meters = 200
~~~

Answer 3

1. meters = 100 and feets does not exist
2. meters = 100 and feet = 328.08
3. meters = 200 and feet = 328.08

Note that feets is not update after meters has been changed on 3rd l

Question 4

What is the definition of an algorithm?

Answer 4

It is a finite list of instructions
describing a set of computations that when executed on a set of
inputs will proceed through a sequence of well-defined states and
eventually produce an output.

Question 5

What is the definition of flow of control?

Answer 5

It is the order in which the instructions from an imperative program is executed.

By default, instructions are executed one after another,** starting from the top. However, we can change this by using, flow control statements (e.g. if statements).

Question 6

Explain primitives

Answer 6

Primitives are the building blocks, like atoms, of a programming language.

The primitive constructs in Python include literals (e.g., the number 3.2 and the string ‘abc’) and infix operators (e.g., + and /).

Question 7

Explain syntax

Answer 7

Syntax determines when the combination of primitives is legal. See examples below in Python

3.2 + 3.2 - syntatically valid
3.2 3.2 - not syntatically valid

Question 8

Explain static semantics

Answer 8

Statics semantics determines that syntatically correct code is meaningful.

3.2 + 'hello world' is syntatically correct but fails in terms of static semantics

Question 9

Explain semantics

Answer 9

Semantics is the meaning of code that is both syntatically correct and has proper statics semantics.

Code can only be interpreted in one way by computers.

It can happen that the programmer was not able to convey the desired meaning to the code he/she created, and execution of program by the computer does not yield the expected outcome.

Question 10

What is the Church-Turing thesis?

Answer 10

Is the thesis that if a problem is computable, then a Turing Machine can compute it.

Question 11

What is the concept of Turing completeness?

Answer 11

Whenever a proposed programming language is able to simulate a Turing Machine, this language is said to be Turing complete.

The interest part is solution in one Turing-complete programming language can be converted to another as long as the latter is also Turing complete.

Question 12

What is a flowchart?

Answer 12

It is a visual representation of the flow of control from an imperative program.

Question 13

What is source code?

Answer 13

It is the code written by the programmer as the programmer was the source for the code written.

Question 14

What is the difference between interpreted and compiled programming languages?

Question 15

What is the difference between low-level versus high-level programming languages?

Question 16

What is the difference between general versus targeted to an application domainprogramming languages?