Last Updated: 20/07/2021
Lesson 5 - switch
Lessons >> Basics >> Lesson 5 - switch
Lesson Contents
Using "switch" to control program flow
Learning the "switch" syntax
Comparing a single value in a "case"
Comparing multiple values in a "case"
Understanding the "default "
Understanding "break"
Nesting a "switch" statement in a "for loop"
Nesting a "for loop" in a "switch" statement
Swapping a value between two variables
Using a variable to change the start value of a "for loop"
Example 1: switchv1.ino
Click to Download code:switchv1.ino
Simple introduction to the "switch" staement
Comparinf single value cases.
Using the" default"
break;
/* 21/07/2021
switchv1
Basic use of the switch statement
*/
//An int is an integer, a Number, any value between -32,768 and 32,767
int q;
int w;
void setup() {
// Serial.begin(9600) starts serial communication. 9600bps bits per second = 1200 characters per second
Serial.begin(9600);
//Send script name
Serial.println("switchv1...");
//this will print a blank line
Serial.println(" ");
}
void loop() {
//q starts with a value of Zero, the loop continues while q smaller than 20
for (q = 0; q < 20; q++) {
Serial.print("q: ");
Serial.println(q);
switch(q){
//q is equal to 1
case 1:
Serial.println("q is equal to 1");
break;
//q is equal to 2
case 2:
Serial.println("q == 2");
break;
//q is equal to a value we have not tested for
default:
Serial.println("q is not equal to 1 or 2");
break;
}
//the following if statements are all covered by the switch statement above
/*
if(q == 1){
}
if(q == 2){
}
if(q > 2){
}
if(q<1){
}
*/
}
//delay outside the for loop
delay(100);
}
Example 2: switchv2.ino
Click to Download code:switchv2.ino
Using "case" to compare a range of values.
/* 21/07/2021
switchv2
Purpose, switch statement comparing multiple values in a single case
*/
//An int is an integer, a Number, any value between -32,768 and 32,767
int q;
int w;
void setup() {
// Serial.begin(9600) starts serial communication. 9600bps bits per second = 1200 characters per second
Serial.begin(9600);
//Send script name
Serial.println("switchv2...");
//this will print a blank line
Serial.println(" ");
}
void loop() {
//q starts with a value of Zero, the loop continues while q smaller than 20
for (q = 0; q < 20; q++) {
Serial.print("q: ");
Serial.println(q);
switch(q){
case 1:
Serial.println("q is equal to 1");
break;
case 2:
Serial.println("q == 2");
break;
case 5 ... 10:
Serial.println("value from 5 to 10");
break;
default:
Serial.println("q is not equal to 1 or 2");
break;
}
}
//delay outside the for loop
delay(100);
}
Example 3: switchv3.ino
Click to Download code:switchv3.ino
Nested "switch" with "for loop"
Swapping a value between variables
Starting a for loop with a variable value.
/* 21/07/2021
switchv3
Purpose, nesting a for loop in a switch statement
*/
//An int is an integer, a Number, any value between -32,768 and 32,767
int q;
int w;
void setup() {
// Serial.begin(9600) starts serial communication. 9600bps bits per second = 1200 characters per second
Serial.begin(9600);
//Send script name
Serial.println("switchv3...");
//this will print a blank line
Serial.println(" ");
}
void loop() {
//q starts with a value of Zero, the loop continues while q smaller than 20
for (q = 0; q < 20; q++) {
Serial.print("q: ");
Serial.println(q);
switch(q){
case 1:
Serial.println("q is equal to 1");
break;
case 2:
Serial.println("q == 2");
break;
case 5 ... 10:
Serial.println("value from 5 to 10");
//for(w=0;w<15;w++)...normal for loop
//w takes on the value of q instead of 0 in the line above
//this allows us to start our "for loop" at varying start values.
for(w = q;w<15;w++){
Serial.print("w: ");
Serial.println(w);
}
break;
default:
Serial.println("q is not equal to any tested case");
break;
}
}
//delay outside the for loop
delay(100);
}
Additional Resource Links
Don't forget to use the Reference in you Arduino IDE and look at switchl Structures and Comparison Operators for more help on this lesson.Comments
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