The learner will review code and answer questions about the results of using a switch statement on a variable created using the map command.
Switch Statement on Map Command
All the flashcards in this set deal with the code below:
const int sensorMin = 0;
const int sensorMax = 100;
int range;
void setup()
{
Serial.begin(9600);
}
void main()
{
int sensorReading = analogRead(0);
range = map(sensorReading, sensorMin, sensorMax, 0, 3);
switch (range)
{
case 0:
Serial.println("dark");
break;
case 1:
Serial.println("dim");
break;
case 2:
Serial.println("medium");
break;
case 3:
Serial.println("bright");
break;
default:
Serial.println("invalid input");
}
}
This code is displayed in the image below, which will be on each card, but you may want to make note of it before going on.
Question 1 of 10
Switch Statement on Map Command
Correct!
All the flashcards in this set deal with the code below:
const int sensorMin = 0;
const int sensorMax = 100;
int range;
void setup()
{
Serial.begin(9600);
}
void main()
{
int sensorReading = analogRead(0);
range = map(sensorReading, sensorMin, sensorMax, 0, 3);
switch (range)
{
case 0:
Serial.println("dark");
break;
case 1:
Serial.println("dim");
break;
case 2:
Serial.println("medium");
break;
case 3:
Serial.println("bright");
break;
default:
Serial.println("invalid input");
}
}
This code is displayed in the image below, which will be on each card, but you may want to make note of it before going on.
Correct Answer
Got it!
Question 1 of 10
Switch Statement on Map Command
Incorrect
All the flashcards in this set deal with the code below:
const int sensorMin = 0;
const int sensorMax = 100;
int range;
void setup()
{
Serial.begin(9600);
}
void main()
{
int sensorReading = analogRead(0);
range = map(sensorReading, sensorMin, sensorMax, 0, 3);
switch (range)
{
case 0:
Serial.println("dark");
break;
case 1:
Serial.println("dim");
break;
case 2:
Serial.println("medium");
break;
case 3:
Serial.println("bright");
break;
default:
Serial.println("invalid input");
}
}
This code is displayed in the image below, which will be on each card, but you may want to make note of it before going on.
Your Answer
Correct Answer
Got it!
Question 1 of 10
Switch Statement on Map Command
How many unique cases does the switch statement in this program have? (Do not count the default case.)
Question 1 of 10
Switch Statement on Map Command
Correct!
How many unique cases does the switch statement in this program have? (Do not count the default case.)
Correct Answer
4
There are four cases, case 0, case 1, case 2, and case 3.
Question 1 of 10
Switch Statement on Map Command
Incorrect
How many unique cases does the switch statement in this program have? (Do not count the default case.)
Your Answer
Correct Answer
4
There are four cases, case 0, case 1, case 2, and case 3.
Question 1 of 10
Switch Statement on Map Command
Question 1 of 10
Switch Statement on Map Command
Correct!
Suppose our sensor reading maps to 2. What would be printed?
Correct Answer
medium
If the reading is mapped to 2, we will be in case 2 which has lines Serial.println("medium"); and break; so the case 2 will print medium.
Question 1 of 10
Switch Statement on Map Command
Incorrect
Suppose our sensor reading maps to 2. What would be printed?
Your Answer
Correct Answer
medium
If the reading is mapped to 2, we will be in case 2 which has lines Serial.println("medium"); and break; so the case 2 will print medium.
Question 1 of 10
Switch Statement on Map Command
Question 1 of 10
Switch Statement on Map Command
Correct!
True or False: The default case is executed if the range variable is not 0, 1, 2, or 3.
Correct Answer
True
When a switch is done checking its cases, if it has not executed one of them, it will execute the code after default instead.
Question 1 of 10
Switch Statement on Map Command
Incorrect
True or False: The default case is executed if the range variable is not 0, 1, 2, or 3.
Your Answer
Correct Answer
True
When a switch is done checking its cases, if it has not executed one of them, it will execute the code after default instead.
Question 1 of 10
Switch Statement on Map Command
Question 1 of 10
Switch Statement on Map Command
Correct!
True or False: In this example, more than one case can be true at the same time.
Correct Answer
False
Once the sensor is read and the result is mapped to range, range will have exactly one value, either 0, 1, 2, or 3.
Question 1 of 10
Switch Statement on Map Command
Incorrect
True or False: In this example, more than one case can be true at the same time.
Your Answer
Correct Answer
False
Once the sensor is read and the result is mapped to range, range will have exactly one value, either 0, 1, 2, or 3.
Question 1 of 10
Switch Statement on Map Command
Question 1 of 10
Switch Statement on Map Command
Correct!
True or False: Range could be of type float.
Correct Answer
False
We should never use float variables for values we are going to test for equality or as arguments in functions that take integer arguments. The switch here is testing equality in each case, so it should not be used with a float variable.
Question 1 of 10
Switch Statement on Map Command
Incorrect
True or False: Range could be of type float.
Your Answer
Correct Answer
False
We should never use float variables for values we are going to test for equality or as arguments in functions that take integer arguments. The switch here is testing equality in each case, so it should not be used with a float variable.
Question 1 of 10
Switch Statement on Map Command
If there were no break; command at the end of case 0, what would the output of that case be?
Question 1 of 10
Switch Statement on Map Command
Correct!
If there were no break; command at the end of case 0, what would the output of that case be?
Correct Answer
dark & dim
So our program would look like:
case 0:
Serial.println("dark");
case 1:
Serial.println("dim");
break;
So, if we look at the code in case 0, the Serial.println("dark"); will print dark. Since the break; is missing, the switch will continue to execute the code it finds until it reaches a break; (or the end of the switch statement). Therefore, the code under case 1 will be executed as well; Serial.println("dim") will print dim, and then break; will end the switch. Thus, the program modified as above will print dark and then dim.
Question 1 of 10
Switch Statement on Map Command
Incorrect
If there were no break; command at the end of case 0, what would the output of that case be?
Your Answer
Correct Answer
dark & dim
So our program would look like:
case 0:
Serial.println("dark");
case 1:
Serial.println("dim");
break;
So, if we look at the code in case 0, the Serial.println("dark"); will print dark. Since the break; is missing, the switch will continue to execute the code it finds until it reaches a break; (or the end of the switch statement). Therefore, the code under case 1 will be executed as well; Serial.println("dim") will print dim, and then break; will end the switch. Thus, the program modified as above will print dark and then dim.
Question 1 of 10
Switch Statement on Map Command
Question 1 of 10
Switch Statement on Map Command
Correct!
True or False: The case statement is somewhat like nested if - else statements.
Correct Answer
True
Case statements function very much like if - else statements, first checking one condition, then checking another condition (else if) etc.
Question 1 of 10
Switch Statement on Map Command
Incorrect
True or False: The case statement is somewhat like nested if - else statements.
Your Answer
Correct Answer
True
Case statements function very much like if - else statements, first checking one condition, then checking another condition (else if) etc.
Question 1 of 10
Switch Statement on Map Command
What would the output be if there were no default statement and range was equal to 4?
Question 1 of 10
Switch Statement on Map Command
Correct!
What would the output be if there were no default statement and range was equal to 4?
Correct Answer
There would be no output
Without the default statement, a switch will not execute any of its code if it reaches the end of the case list without matching its input. So if the default statement was not here and range was 4, it would look through all the cases (0, 1, 2, and 3) and, not matching the value 4, would simply end.
Question 1 of 10
Switch Statement on Map Command
Incorrect
What would the output be if there were no default statement and range was equal to 4?
Your Answer
Correct Answer
There would be no output
Without the default statement, a switch will not execute any of its code if it reaches the end of the case list without matching its input. So if the default statement was not here and range was 4, it would look through all the cases (0, 1, 2, and 3) and, not matching the value 4, would simply end.
Question 1 of 10
Switch Statement on Map Command
True or False: If range were of type Boolean, the case statements could be based on conditions such as TRUE, FALSE, HIGH, & LOW.
Question 1 of 10
Switch Statement on Map Command
Correct!
True or False: If range were of type Boolean, the case statements could be based on conditions such as TRUE, FALSE, HIGH, & LOW.
Correct Answer
True
Boolean variables would match conditions like TRUE, FALSE, HIGH, LOW, 0, or 1.
Question 1 of 10
Switch Statement on Map Command
Incorrect
True or False: If range were of type Boolean, the case statements could be based on conditions such as TRUE, FALSE, HIGH, & LOW.
Your Answer
Correct Answer
True
Boolean variables would match conditions like TRUE, FALSE, HIGH, LOW, 0, or 1.
Question 1 of 10
Switch Statement on Map Command
Question 1 of 10
Switch Statement on Map Command
Correct!
If the sensor input was 77, which case would this be mapped to?
Correct Answer
2
When the map(sensorReading, sensorMin, sensorMax, 0, 3); function runs, it takes
(sensorReading - sensorMin) * (3 - 0) / (sensorMax - sensorMin) + 0
which for our values is
(77 - 0) * (3 - 0) / (100 - 0) + 0 = 2.31
Actually, it will give 2 since all the values being evaluated are int types, it will truncate the division to 2 (and then add 0).
Therefore the code range = map(sensorReading, sensorMin, sensorMax, 0, 3); in this case will make range = 2 and the switch will start executing the code under case 2.
Question 1 of 10
Switch Statement on Map Command
Incorrect
If the sensor input was 77, which case would this be mapped to?
Your Answer
Correct Answer
2
When the map(sensorReading, sensorMin, sensorMax, 0, 3); function runs, it takes
(sensorReading - sensorMin) * (3 - 0) / (sensorMax - sensorMin) + 0
which for our values is
(77 - 0) * (3 - 0) / (100 - 0) + 0 = 2.31
Actually, it will give 2 since all the values being evaluated are int types, it will truncate the division to 2 (and then add 0).
Therefore the code range = map(sensorReading, sensorMin, sensorMax, 0, 3); in this case will make range = 2 and the switch will start executing the code under case 2.
Question 1 of 10
Score
You have answered 5 of 10 questions correctly.
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Question 1 of 10
- Author
- Published
- 6/2/2015
- Last Updated
- 6/2/2015
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Switch Statement on Map Command by Fox Valley Technical College is licensed under a Creative Commons Attribution 3.0 Unported License.