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--- en:iot-open:programming_fundamentals_rtu:program_control_structures [2018/01/23 09:43] – Agrisnik
+++ en:iot-open:programming_fundamentals_rtu:program_control_structures [2020/07/20 09:00] (current) – external edit 127.0.0.1
@@ Line 95: / Line 95: @@
 ==== Boolean operators ====
-The Boolean logical operators
+Three Boolean logical operators in the Arduino environment are following:
-  * ! (logical not) -
+  * ! (logical NOT) - reverses the logical state of the operand. If a condition is //TRUE// the logical NOT operator will turn it to //FALSE// and the other way around.
-  * && (logical and) -
+  * && (logical AND) - the result is //TRUE// when the both operands on the left and on the right of the operator are //TRUE//. If even one of them is //FALSE// the result is //FALSE//.
-  * || (logical or) -
+  * || (logical OR) - result is //TRUE// when at least one of the operands on the left and on the right of the operator is //TRUE//. If both of them are //FALSE// the result is //FALSE//.
+Examples:
+<code c>
+//logical NOT
+if (!a) { //the statement inside "if" will execute when the "a" is FALSE
+  b = !a; //the reverse logical value of "a" is assigned to the variable "b"
+}
+//logical AND
+if (a && b){  //the statement inside "if" will execute when the values both of the "a" and "b" are TRUE
+  //statement
+}
-===== Switch =====
+//logical OR
-Switch...case
+if (a || b){  //the statement inside "if" will execute when at least one of the "a" and "b" values is TRUE
+  //statement
+}
+</code>
+===== Switch case statement =====
+Switch statement similar like //if// statement controls the flow of program. The code inside //switch// is executed in various conditions. A //switch// statement compares the values of a variable to the specified values in the //case// statements. Allowed data types of the variable are //int// and //char//. The //break// keyword exits the //switch// statement.
+Examples:
+<code c>
+switch (x) {
+   case 0:  //executes when the value of x is 0
+   // statements
+   break;   //goes out of the switch statement
+   case 1:  //executes when the value of x is 1
+   // statements
+   break;   //goes out of the switch statement
+   default:  //executes when none of the cases above is true
+   // statements
+   break;   //goes out of the switch statement
+}
+</code>
+**Check yourself**
+. Which code part is correct?
+  * if (value == 1) digitalWrite(13, HIGH)
+  * if (value == 1); digitalWrite(13, HIGH)
+  * if (value == 1) DigitalRead(13,1)
+. What is the output of the next code part?
+<code c>
+int x = 0;
+    switch(x)
+    {
+      case 1: cout << "One";
+      case 0: cout << "Two";
+      case 2: cout << "Hello, world!";
+    }
+    </code>
+. In which cases 'switch structure' should be used?

en/iot-open/programming_fundamentals_rtu/program_control_structures.1516700623.txt.gz · Last modified: 2020/07/20 09:00 (external edit)