Initial Commit

Java/Processing/processing-3.3.6/modes/java/examples/Basics/Data/VariableScope/VariableScope.pde

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+/**
+ * Variable Scope. 
+ * 
+ * Variables have a global or local "scope". 
+ * For example, variables declared within either the
+ * setup() or draw() functions may be only used in these
+ * functions. Global variables, variables declared outside
+ * of setup() and draw(), may be used anywhere within the program.
+ * If a local variable is declared with the same name as a
+ * global variable, the program will use the local variable to make 
+ * its calculations within the current scope. Variables are localized
+ * within each block, the space between a { and }. 
+ */
+ 
+int a = 80;  // Create a global variable "a"
+
+void setup() {
+  size(640, 360);
+  background(0);
+  stroke(255);
+  noLoop();
+}
+
+void draw() {
+  // Draw a line using the global variable "a"
+  line(a, 0, a, height);
+  
+  // Create a new variable "a" local to the for() statement 
+  for (int a = 120; a < 200; a += 2) {
+    line(a, 0, a, height);
+  }
+  
+  // Create a new variable "a" local to the draw() function
+  int a = 300;
+  // Draw a line using the new local variable "a"
+  line(a, 0, a, height);  
+  
+  // Make a call to the custom function drawAnotherLine()
+  drawAnotherLine();
+  
+  // Make a call to the custom function setYetAnotherLine()
+  drawYetAnotherLine();
+}
+
+void drawAnotherLine() {
+  // Create a new variable "a" local to this method
+  int a = 320;
+  // Draw a line using the local variable "a"
+  line(a, 0, a, height);
+}
+
+void drawYetAnotherLine() {
+  // Because no new local variable "a" is set, 
+  // this line draws using the original global
+  // variable "a", which is set to the value 80.
+  line(a+2, 0, a+2, height);
+}