Algorithms, precise instructions on how to to accomplish a specific task, are at the core of computer science.

Sorting information

Selection sort

The idea of selection sort is:

• Move the smallest number in the array to index 0.
• Move the second smallest number to index 1.
• Move the third smalles number in the array to index 2.
• Etc.

In other words:

• Examine the array starting from index 0. Swap the following two numbers with each other: the number at index 0, and the smallest number in the array starting from index 0.
• Examine the array starting from index 1. Swap the following two numbers with each other: the number at index 1, and the smallest number in the array starting from index 1.
• Examine the array starting from index 2. Swap the following two numbers with each other: the number at index 2, and the smallest number in the array starting from index 2.
• Etc.

Static or not

Methods in Java can be divided into two groups, based on whether they have the static modifier or not.

Methods without the static modifier are instance methods. Methods with the static modifier are class methods

Instance methods are methods that are associated with an object, can process the objects variables and can call the object's other methods. Instance methods specifically CAN use the this modifier, which refers to the variables associated with the specific object, that is calling the instance method.

Class methods can't use the this modifier, meaning that they can only access the variables they are given as parameters or that they create themselves.

Built-in sorting algorithms in Java

Arrays can be sorted (into their natural order) using the class method sort of the Arrays-class.