Chapter 1

Question 1

Natural Languages

Answer 1

Languages that people speak (like English) which are not designed by people but evolved naturally

Question 2

Formal Languages

Answer 2

Languages that are designed by people for specific applications (like music score or programming languages)

Question 3

For which application did people design programming languages as a formal language?

Answer 3

To express computations

Question 4

How are formal languages’ syntax rules like?

Answer 4

They have strict syntax rules that govern the structure of statements. For eg - 3 + 3 = 6 has a correct syntax in Math but 3+ =5–$8 hasn’t.

Question 5

Syntax Rule Flavors - how many and what are they?

Answer 5

Two, tokens and structure

Question 6

What are tokens in a formal language?

Answer 6

Basic elements of the language, such as words, numbers and chemical elements (for chemistry). For eg, + is a token in Maths and Fe is a token in chemistry (for iron).

Question 7

Token syntax rule in a formal language

Answer 7

Have to contain only valid tokens in a statement. For example, $ is not a valid token in Maths, but + is.

Question 8

Structure syntax rule in a formal language

Answer 8

Tokens has to be combined in a correct way. For eg - 3 + / 3 is incorrect because although + and / are correct tokens in Maths, they can’t be immediately after one another.

Question 9

Parsing

Answer 9

A process of analyzing a string of symbols, either in natural or formal languages, conforming to the rules of a formal grammar of the language by breaking it into parts

Question 10

Difference between natural and formal language: Ambiguity

Answer 10

Natural -> Full of ambiguity, people deal with this by using contextual clues and other info
Formal -> Nearly or completely unambiguous, any statements has exactly one meaning regardless of context

Question 11

Difference between natural and formal language: Redundancy

Answer 11

Natural -> Lots of redundancy and verbose because of ambiguity and to reduce misunderstandings
Formal -> Less redundant and more concise

Question 12

Difference between natural and formal language: Literalness

Answer 12

Natural -> Full of idiom and metaphor, for eg - under the weather
Formal -> Mean exactly what they say

Question 13

How can a computer program be understood and why?

Answer 13

Because the meaning of a computer program is unambiguous and literal, it can be understood entirely by analysis of the tokens and structure.

Question 14

Difference between natural and formal language: Errors

Answer 14

Small errors in spelling and punctuation, which can be ok in a natural language, can make a big difference in a formal language.

Question 15

What is a value in a program?

Answer 15

One of the basic things a program works with, like integer 39 or string “Hello”

Question 16

What are types in a programming language?

Answer 16

A type is a category of values, like type ‘int’ for whole numbers (integers).

Question 17

What is exponentiation and what is the operator in python?

Answer 17

Raising a number to a power, like 2 to the power of 3 and in python, it is **.

Question 18

What is a program?

Answer 18

A sequence of instructions that specifies how to perform a computation

Question 19

Three types of computation

Answer 19

Mathematical, Symbolic and Graphical

Question 20

Example of Symbolic Computation

Answer 20

Searching and replacing text in a document

Question 21

Basic instructions of programming languages

Answer 21

Input, Output, Math, Conditional Execution, Repetition

Question 22

Examples of Input instruction

Answer 22

Get data from the keyboard, a file, the network, or some other device

Question 23

Examples of output instruction

Answer 23

Display data on the screen, save it in a file, send it over the network, etc.

Question 24

Examples of Math instruction

Answer 24

Perform basic mathematical operations like addition and multiplication

Question 25

Examples of Conditional Execution instruction

Answer 25

Check for certain conditions and run the appropriate code

Question 26

Examples of Repetition instruction

Answer 26

Perform some action repeatedly, usually with some variation

Question 27

Is every program, including super complex ones, made up of only basic instructions? Explain.

Answer 27

Yes. You can think of programming as the process of breaking a large, complex task into smaller and smaller subtasks until the subtasks are simple enough to be performed with one of these basic instructions.

Question 28

Meaning of Problem Solving

Answer 28

The ability to formulate problems, think creatively about solutions, and express a solution clearly and accurately

Question 29

Thinking like a computer scientist is a combination of what?

Answer 29

It combines some of the best features of mathematics, engineering, and natural science.

Question 30

Like mathematicians, what computer scientists do?

Answer 30

Like mathematicians, computer scientists use formal languages to denote ideas (specifically computations).

Question 31

Like Engineers, what computer scientists do?

Answer 31

Like engineers, they design things, assembling components into systems and evaluating tradeoffs among alternatives.

Question 32

Like Scientists, what computer scientists do?

Answer 32

Like scientists, they observe the behavior of complex systems, form hypotheses, and test predictions.

Question 33

What is debugging?

Answer 33

Process of tracking down (and fixing) programming errors which are called bugs.

Question 34

What is a operator?

Answer 34

A special symbol that represents a simple computation like addition, multiplication, or string concatenation

Question 35

What is a prompt?

Answer 35

Characters displayed by the interpreter to indicate that it is ready to take input from the user

Question 36

What is protability?

Answer 36

A property of a program that can run on more than one kind of computer

Question 37

What is syntax?

Answer 37

The rules that govern the structure of a program