Learning Java/Programming tips

When to use methods

The ideal method only handles one function, and is named approprately. Using methods increases readability of your code and makes it easier to expand or change your software. You can also call your methods from seperate places, reducing the total number of lines of code. Methods are also used to retrieve data from an object and store data in objects. These methods are called getters and setters. Example: <pre> public class Customer {

  private String firstName;
  private String lastName;

  public String getFirstName() {
     return firstName;
  }

  public void setFirstName(String firstName) {
     this.firstName = firstName;
  }

  public String getLastName() {
     return lastName;
  }

  public void setLastName(String lastName) {
     this.lastName = lastName;
  }

} </pre>

Methods are allowed to call other methods, but only if they have a different functions. Try using common sense when deciding whether use methods or not. There are multiple analysis tools to see if you are using methods right and effeciently. You should avoid having methods with a lot of lines of code, it often (but not always) indicates that the method can be broken up in smaller methods.

About Arrays

Arrays should be used for variables that have something to do with each other. Basically, arrays are a sets of variables, and arrays are a variable themselves. Here is how to make an array set. <pre> [class]() [var-name]; //Or... int() var; </pre> To specify the length of an array: <pre> var=new var(LENGTH); //Put into one statement int() myInts = int(LENGTH); </pre> LENGTH = array size. It is simply how many items are in the array.

You need to initialize each part of the array. To "access" the members of the array: <pre> myInts(2)==3; int temp = myInts(3); </pre> Note: Do NOT use arrays when the members have nothing to do with each other. This causes code errors!

Basic Tips for Improving Code

Code formatting

Code formatting is necessary to understand your code more easily. For example, the following is very hard to understand because it is not properly formatted: <pre> public class MessyCoding extends Coding {public static void main(String args[] ){System.out.println ("This is messy coding. Don't do this");System.exit(0);}} </pre> In much better format: <pre> public class CleanCoding extends Coding {

  public static void main(String args[])
  {
     System.out.println("This is clean coding. DO THIS!!");
     System.exit(0);
  }

} </pre> Notice that the code is easier to understand. Every single new block that has { and } should have whitespace preceding it. Example: <pre> public class CleanCoding extends Coding {

  public static void main(String args[])
  {
     try{
        try{
            ...;
        }
        ...;
     }
     ...;
  }
  ...;

} </pre>

To further improve the readability of your code, you should insert one empty line between methods: <pre> public null method1() {

} </pre> A good alternative is: <pre> public null method2() {

} </pre> You should make a new line after every statement/declaration. If a statement is too long, you can break it down.

Some Integrated Development Environments like Netbeans IDE have an auto-formatting function built in.

Good Comments

Good comments can help make your code look neat. They should tell what you are doing overall, not what you are doing on each line. For example, you can comment an if statement if it is kind of complex, but not every statement has to be commented:

<pre> // tests for parity, sign, and size if( x%2 == 0 && x > 0 && x < 1000 ) { System.out.println("x is a positive, even, integer less than 1000");

   if( x%3 == 0 ) // tests if divisible by 3
       x++;

} </pre>

An example of bad commenting would be:

<pre> if( i1 == i2 | i1 == i3 ) // Check if i1 is equal to i2 and i3 {

  System.out.println( "YES!" ); // Print Yes! to the command line
  i1= i1 + 1; // Add 1 to i1

} </pre>

Quick way to convert numbers to strings

There will be a lot of times you need a String and you're working with numbers. This is one of the faster ways to convert numbers to String, but it's not very neat. <pre> int a = 5; double b = 3;

String a_as_string = "" + a; String b_as_string = "" + b;

or

String a_as_string = String.valueOf(a); String b_as_string = String.valueOf(b); </pre>

Project: Java

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