Chapter 9: Algorithms and Programming

algorithm

is a set of steps to do a task. 

Natural language

is our native speaking and writing language, so it is much easier for people to use and understand.

Programming languages

are very strict with their syntax, which is like their grammar and structure.

Pseudocode

is used to map out a program’s structure before beginning to write the code and uses a combination of natural and programming languages.

Flowcharting

helps to visualize how the program will be structured.

Clarity

refers to how easy it is to understand. 

Readability

is important to help programmers understand a program. 

Variables

are placeholders for values a program needs to use. 

Data types

are the way computers assign some meaning to these binary digits. 

Strings

are text fields that are just a series of characters and are denoted with quotation marks around the string field. 

Integers

can be used in mathematical operations and expressions, whereas strings (text fields) cannot.

**“Fractional” Numbers**

These are numbers with a decimal point, even if a number has 0 (zero) for the decimal value, such as 52.0. 

MOD

is the symbol used for modulus math in many programming languages.

**Assignment Statements**

To assign a value to a variable, the assignment operator is used.

Expressions

are calculations to be evaluated to an answer or single value.

Boolean Values

\

are one of the foundations of computer code.

Boolean expressions

can be simple or compound.

**AND LOGICAL OPERATOR**

To be true, both of the operands on either side of the AND operator must be true when evaluated individually.

**OR LOGICAL OPERATOR**

For the OR operator, either or both of the operands can be true for the condition to be true.

**NOT LOGICAL OPERATOR**

With the NOT operator, if a condition was true, then NOT makes it false.

**Program Statements**

All programs can be written using a combination of only three types of statements.

**Sequential**

These are statements that are executed as written in order in the program.

Selection Statements

These are a key component to many programs.

**Iterative**

are also referred to as repetitive statements or loops.

**REPEAT n TIMES Loop**

This loop will repeat a specified number of times: “n” is a variable that must be set to a positive integer for the loop to run.

**REPEAT UNTIL (Condition) Loop**

has a condition to evaluate at each iteration of the loop.

**Combining Algorithms**

One of the key features of algorithms is that once they are created, you can use them over and over, combine them for more complex problem solving, or modify them for a new use.

**Common Algorithms**

Determining the maximum or minimum number from two or more numbers.

Robots

There are four commands you are responsible for understanding and using.

MOVE_FORWARD

One command the robot can follow is

CAN_MOVE

can be used in an IF statement in your code to navigate through the maze.

Lists

in a program can be a collection of numbers, words, phrases, or a combination of these.

**List Indices**

Individual items in a list are called elements and are accessed by position using an index.

Index positions

are always integers and are enclosed within square brackets \[index\].

INSERT

command causes elements to the right of the indicated index position, i, to shift right one position to make room for the new element.

APPEND

command will add the new element to the end of the list, so no index position is needed.

REMOVE

command deletes the element at the provided index position and shifts the remaining elements one position to the left.

Traversing

a loop that will automatically repeat the code for each element in the list.

**Searching**

deals with finding the needed element from everything in the dataset or determining that it is not there.

Linear searches

also called sequential searches, check each individual record, starting at the beginning and going to the end, one after the other in order to either find the desired data or to determine it is not in the dataset.

Binary searches

are far more efficient than linear searches.

Procedures

are also called functions in some programming languages.

Parameters

allow the calling program to send values to the procedure.

Procedural abstraction

You only need to know the name of the procedure, the number and type of parameters, and the output to expect.