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content/ta/spring2018/cpsc220/feb20.md

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+# Lecture for February 20th
+
+## Reading a File
+
+You can get input from a file instead of from the terminal
+
+```java
+FileInputStream fileIn = new FileInputStream("myFile.txt");
+// Our familiar Scanner
+Scanner scnr = new Scanner(fileIn);
+// We can use our usual Scanner methods
+String line = scnr.nextLine();
+fileIn.close(); // Remember to close the file when you're finished with it!
+```
+
+### Reviewing Scanner Methods
+
+To understand some of the Scanner methods we need to be aware of the "newline" character. This character is equivalent to the `Enter` button on the keyboard.
+
+`scnr.nextLine()` This get's all the characters in the buffer up to the newline character.
+
+`scnr.next()` Grabs the characters in the next "token". Tokens are usually separated by any whitespace type character (spaces, enters, tabs, etc.)
+
+## Writing to a File
+
+Prints information to a file instead of to the screen
+
+```java
+FileOutputStream fileOut = new FileOutputStream("myOutfile.txt");
+PrintWriter out = new PrintWriter(fileOut);
+out.println("Print this as the first line.");
+out.flush(); // Pushes the file changes to the file
+fileOut.close(); // If you forget this then it won't remember your changes
+```
+
+## Arrays
+
+Arrays are containers of fixed size. It contains a fixed number of values of the **same type**. (Ex: 10 integers, 2 strings, 5 booleans)
+
+Declaration
+
+```java
+int[] array; // This declares an integer array
+```
+
+Initialization
+
+```java
+array = new int[7]; // This states that this array can hold up to 7 integers
+```
+
+Storing a value in an array
+
+- Square bracket notation is used
+
+```java
+int[] array = new int[7];
+array[0] = 5; // Stores 5 into the first slot
+```
+
+Now let us attempt to retrieve the value
+
+```java
+int temp = array[0];
+System.out.println(temp); // Prints "5"
+```
+
+### Traversing an Array
+
+Let's say we have the following array
+
+```java
+int[] numbers = {3, 5, 2, 7, 9};
+```
+
+Let's print out each of the values in the array
+
+```java
+for (int i = 0; i < numbers.length; i++) {
+    System.out.print("value in " + i " is " + numbers[i]);
+}
+```
+
+### Finding the maximum value in an Array
+
+```java
+int highest = numbers[0];
+for (int i = 0; i < numbers.length; i++) {
+    if (numbers[i] > highest) {
+        highest = numbers[x];
+    }
+}
+```
+