Changes between Initial Version and Version 1 of ControlSystems/SoftwareTeam/Training/GettingStarted/Conditionals

Timestamp:

Nov 4, 2019, 3:21:54 PM (6 years ago)

Author:

David Albert

Comment:

--

ControlSystems/SoftwareTeam/Training/GettingStarted/Conditionals

@@ +1 @@
+Programs need to be able to react differently to varying data.  Conditional statements let us do this.  For example, a robot must be able to monitor its sensors to prevent collisions.  Consider (and try running) the following program:
+
+1. Create a new folder in your Java Projects folder named Conditional Example 
+1. Create a new file (New->File)
+1. Cut and paste this program into the file.
+{{{
+public class ConditionalExample {
+    public static void main(String args[]) {
+        int rangeInInches;
+
+        rangeInInches = 10;
+
+        if (rangeInInches < 20) {
+           System.out.println("stop motors so we don't crash!");
+        } else {
+           System.out.println("full speed ahead!");
+        }
+    }
+}
+}}}
+1. Save the program as !ConditionalExample.java (notice how the name of the file must match the name of the class)
+
+=== Running the program
+Run the program using the debugger with a breakpoint set on the first executable line (rangeInInches=10); 
+* Step through the program using the stepover tool and observe the flow of the program.
+* Restart the program using the restart tool
+* Change the values stored in the variable rangeInInches to 25 and observe the flow of the program.
+
+=== Extra Credit ===
+Java allows you to have multiple conditionals using the syntax:
+{{{
+     if (<condition 1>) {
+        // do this if condition 1 is true
+        // also do this if condition 1 is true
+     } else if (<condition 2>) {
+        // do this if condition 1 was not true but condition 2 is true
+     } else {
+        // do this if neither condition 1 nor condition 2 were true
+     }
+}}}
+You can have as many ''else if'' clauses as you wish.
+
+Some things to note:
+* The conditions are always placed within parentheses
+* The conditions are logic statements that must evaluate to true or false (e.g. (a < 10))
+* The conditions are evaluated in order and the '''first''' condition that matches is executed, the rest are skipped
+* The ''else if'' and ''else'' clauses are optional