Arrays and ArrayLists in Java

March 3, 2016 by Alex Clarke

Arrays

Arrays are very useful to know because they are a standard that is built into C, its children languages (Java, C++, etc) and other languages such as Python. An array allows the programmer to store multiple different variables, of the same type, into a single list that can be called upon as a certain object. This, coupled with loops, makes it unnecessary for the programmer to know how many variables are being stored. It does this by allowing the programmer to create one thing (the array) instead of creating multiple different variables that would all be individually initialized and named.

The String Class and the Integer Class

February 3, 2016 by Alex Clarke

The String and Integer Classes are very useful to know. Some of their methods (runnable pieces of code) are very useful to everyday coding.

The String Class

substring(start, end) – substring can be use to grab a certain section of a string. It is used by giving it a start and end position. If no end position is given it assumes the end of the string. Also important to note, the end position is actually one more than what is grabbed. You can just use the substring right away or you can save it either over the original or in its own variable. You can see in this example:

Boolean Expressions, If Statements and Loops

January 21, 2016December 26, 2015 by Alex Clarke

Boolean Expressions

A boolean expression is evaluated by using certain operators to come to a true or false answer. The operators are:

== – Returns true if the values on either side are equal

!= – Returns true if the values on either side are not equal

< – Returns true if the value on the left is less than the value on the right

<= – Returns true if the value on the left is less than or equal to the value on the right

> – Returns true if the value on the left is greater than the value on the right

>= – Returns true if the value on the left is greater than or equal to the value on the right

&& – (And) Returns true if both values are true.

|| – (Or) Returns true if either value is true

Intro to Variables and Operators

March 19, 2016November 24, 2015 by Alex Clarke

Variables are used for storage of information in a program. They can be addressed by name and have specific types based on the information being stored.

Check out my other posts if you want to learn what an IDE is and how to download one or how to use Eclipse or how to use jGrasp.

Primitive Data Types of Variables

Each of the following number data types allows the user to save an integer or decimal value into variables, if it is within the range.