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Semester 2/Programming 2/Week 1/Week 1 Programming 2.md

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+## Lecture 1
+
+### Files
+
+```java
+import java.utils.*
+import java.io.*
+public void writeAnimalData( String fileName ) throws FileNotFoundException
+{
+	PrintWriter pWriter = new PrintWriter( fileName );
+	for( Animal a: animalCollection )
+	{
+		String lineOfOutput = a.getName() + "" + a.getSpecies();
+		pWriter.println( lineOfOutput );
+	}
+	pWriter.close();
+}
+```
+
+Without using `throws FileNotFoundException`, a compilation error will occur. Any method that may possibly throw an exception must advertise this by using `throws` to discard the error to avoid a crash.
+The method `PrintWriter` itself, also includes the clause, as can be seen in the Java.io documentation.
+
+```java
+public Zoo( String fileName ) throws FileNotFoundException
+{
+	this();
+	readAnimalData( fileName );
+}
+```
+
+This allows us to use the code from the default constructor without duplicating the code. `this();` must be the first keyword in the method.
+
+### Scanner
+
+The scanner class is used to read data from the keyboard / file.
+Once a Scanner object has been created (from Java.util), data can be read: `new Scanner( System.in );`
+A Scanner object breaks the input into tokens separated by whitespaces. Each line of data in the file can be easily read with the following:
+
+```java
+String name = scanner.next();
+String species = scanner.next();
+```
+
+#### Ex
+
+```java
+public void readAnimalData( String fileName) throws FileNotFoundException
+{
+	File dataFile = new File( fileName ); //Create file to write to.
+	Scanner scanner = new Scanner( dataFile ); //Initialise scanner.
+	while( scanner.hasNext() )
+	{
+		String name = scanner.next(); //First token in line.
+		String species = scanner.next(); //Second token in line.
+		StoreAnimal( new Animal( species, name ) ); //Store the tokens as an animal in list.
+		scanner.nextLine(); //Increment to next line.
+	}
+	scanner.close();
+}
+```