Question

Write a switch statement that uses the colour of a swab sample of COVID testing vehicle to send a message to a local doctor. Use the messages given for each colour in the table below. Justify your answer.                                                                                        

Colour	Message
Blue	“No virus”
Yellow	“Needs to be under observation”
Red	“Needs to be admitted in COVID ward”

Answer 1

The question is asked to implement a switch statement that uses the colour of a swab sample of COVID testing vehicle to send a message to a local doctor. Now, switch statement is a special statement in C, which can be used to check different values and based on the checking, corresponding case will be executed. The algorithm to implement the switch statement is given below:

Step 1: Get the sample as input to the program. Also define a function sendMessage() that takes a string as an argument to send it to a local doctor.

Step 2: Write a switch case that will take the argument as the sample. Now implement different cases.

Step 3: If the argument is "Blue", call the function sendMessage( "No virus" ).

Step 4: If the argument is "Yellow", call the function sendMessage( "Needs to be under observation" ).

Step 5: If the argument is "Red", call the function sendMessage( "Needs to be admitted in COVID ward" ).

Step 6: In default case, send "Invalid swab sample or invalid test" to the local doctor or to the laboratory.

If the function sendMessage() is defined to send a message to the doctor, then the switch case implementation in C++/C would be:

switch(sample)
{
   case "Blue":       //in case the sample is blue
       sendMessage("No virus\n");
       break;
   case "Yellow":       //in case the sample is yellow
       sendMessage("Needs to be under observation\n");
       break;
   case "Red":           //in case the sample is red
       sendMessage("Needs to be admitted to COVID ward\n");
       break;
   default:
       sendMessage("Invalid swab sample or invalid test\n");
}

Analysis: At first, the program will get the swab sample from the user. Now this sample variable is passed to the argument of the switch statement. When the sample is Blue, corresponding message will be passed, when it is yellow, corresponding message will be passed and so on. The message is passed using a function sendMessage() that sends the message to a local doctor. After each case, the break statement must be there in order to avoid the other cases. There is also a default case (does not come under any other defined case), that sends a message about the invalid sample or invalid test to the doctor.