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content/ta/spring2018/cpsc220/feb8.md

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+# Lecture for February 8th
+
+##Switch Statements
+
+Another way to perform multiway branching. Comparing a variable and constant values (`String`, `int`, `char`)
+
+Switch statements cannot be used with `boolean`, `double`, or `float`s
+
+### Syntax
+
+```java
+switch (variable) {
+  case value1:
+    // Do something
+    break;
+  case value2:
+    // Do something else
+    break;
+  //...
+  default:
+    // If all else fails do this
+    break;
+}
+```
+
+`case` is a reserved word that means "when our variable in consideration is equal to..."
+
+If you forget the `break` keyword, then the program will keep doing the work of all the statements until it hits a `break` keyword.
+
+### Example Switch Syntax
+
+```java
+switch (birthday) {
+  case 1: 
+    birthstone = "garnet";
+    break;
+  case 2:
+    birthstone = "amethyst";
+    break;
+  // ....
+  default:
+    System.out.println("Not valid");
+    break;
+}
+```
+
+## Comparing Strings Relationally
+
+Comparing strings are based on the ASCII value of characters
+
+Sorting strings will result in strings being in alphabetical or reverse alphabetical order. The values of the strings are compared character by character from the left with each ASCII value.
+
+To compare strings use the `compareTo()` method.  Here is the format of the call
+
+```java
+str1.compareTo(str2)
+```
+
+This returns a *negative number* when `str1` is less than `str2`
+
+This returns `0` when `str1` is equal to `str1`
+
+This returns a *positive number* when `str1` is greater than `str2`
+
+### Example
+
+```java
+String a = "apple";
+String b = "banana";
+
+int x = a.compareTo(b); // x = -1
+
+int y = b.compareTo(a); // y = 1
+```
+
+## Ternary Operator
+
+With a ternary operator, you can shorten statements where a value is determined by an if statement
+
+```java
+String output = "";
+if (movieRating > 4) {
+  output = "Fan favorite";
+} else {
+  output = "Alright";
+}
+```
+
+Is equivalent to
+
+```java
+String output = "";
+output = (movieRating > 4)? "Fan favorite": "Alright";
+```
+
+### Another Example
+
+```java
+double shipping;
+if (isPrimeMember) {
+  shipping = 0;
+} else {
+  shipping = 3.99;
+}
+```
+
+Is equivalent to
+
+```java
+double shipping = (isPrimeMember)? 0: 3.99;
+```
+