Searching and sorting algorithms

algorithm

set of instructions that describes how to solve a problem

decomposition

breaking down a problem into smaller, more manageable chunks. In programming this means breaking down an algorithm into smaller problems that can be solved on their own.

abstraction

the process of removing unnecessary detail from a problem so that the important details can be focused on.

pseudocode

a type of structured English for describing algorithms, it allows the designer to focus on the logic of the algorithm without being distracted by the syntax of the programming language

sequence

The statements are executed in the order they are written

selection statement

An IF statement is a ?, the next statement to be executed depends on whether the condition being tested is true or false

iteration

Iteration means repetition of a block of code until a specific result occurs or until a set number of times has been reached, FOR…ENDFOR, WHILE…ENDWHILE,…REPEAT…UNTIL

integer

a whole number

float

number with a decimal point

boolean

can only be true or false

character

a single alphabetic or numerical character

string

one or more characters enclosed in quote marks

linear search

identify search term, look at first item on the list, compare with the search term, if the current term is the same as search term then found=true, else repeat until search term is found. does not need to be in order

binary search

must be in order. with each loop, half the data is removed from the search.

bubble sort

 Each item in a list is compared to the one next to it, and if it is greater, they swap places. At the end of one pass through the list, the largest item is at the end of the list. This is repeated until the items are sorted.

merge sort

What type of sorting repeatedly divided a list into two until all the elements are separated individually.The algorithm looks at the individual elements and compares them as pairs. Each pair is sorted into order.The pairs are then compared, starting with the first number in each pair. If the left hand number is smaller than the right hand number, it is placed in order. The comparison then moves up to the second number on the left hand side and the process repeats. If the right hand number is smaller, it is placed in order and the comparison moves to the next number on that side.

variable

a named unit of data that is assigned a value.

trace tables

used to allow programmers to trace the value of variables as each line of code is executed. The values of the variables are displayed in a table and assist the programmer in identifying any potential errors.