C Interview Questions on Switch Statement

We discuss various C Language interview questions about Switch Statement.

Interview Questions

1. What is the use of a Switch statement?
2. Can you give an example of a Switch Statement?
3. Can a switch case consist of variable values?
4. Can a switch be used without default?
5. Should default always be at the start of a switch statement?
6. What happens when there is no break in a switch case?
7. Can Switch be used around a character variable?

What is the use of a Switch statement?

The switch statement is a multi-way decision that tests whether an expression matches one of a number of constant integer values, and branches accordingly.

Can you give an example of a Switch Statement?

Below is an example of a switch statement:

#include <stdio.h>
#include <stdlib.h>

int main() {
	int i = 3;

	switch(i){
	case 0 :
		printf("DOT BALL");
		break;
	case 1 :
		printf("SINGLE");
		break;
	case 2 :
		printf("DOUBLE");
		break;
	case 3 :
		printf("TRIPLE");
		break;
	default :
		printf("FOUR OR A SIX");
		break;
	}
}

Can a switch case consist of variable values?

No. Below example would get a compilation error. Case with a variable runs will throw a compilation error.

#include <stdio.h>
#include <stdlib.h>

int main() {
	int i = 3;
	int runs = 5;

	switch(i){
	case runs :
		printf("DOT BALL");
		break;
	default :
		printf("FOUR OR A SIX");
		break;
	}
}

Can a switch be used without default?

Yes. Example program below:

#include <stdio.h>
#include <stdlib.h>

int main() {
	int i = 3;

	switch(i){
	case 0 :
		printf("DOT BALL");
		break;
	case 1 :
		printf("SINGLE");
		break;
	case 2 :
		printf("DOUBLE");
		break;
	case 3 :
		printf("TRIPLE");
		break;
	}
}

Should default always be at the start of a switch statement?

No. It can be anywhere in the switch. Example below:

#include <stdio.h>
#include <stdlib.h>

int main() {
	int i = 3;
	int runs = 5;

	switch(i){
	default :
		printf("FOUR OR A SIX");
		break;
	case 0 :
		printf("DOT BALL");
		break;
	case 1 :
		printf("SINGLE");
		break;
	case 2 :
		printf("DOUBLE");
		break;
	case 3 :
		printf("TRIPLE");
		break;
	}
}

What happens when there is no break in a switch case?

Fall through happens. And all statements until the next break or until the end of switch is reached are executed. Example program below : All the printf statements from case 2 are executed.

#include <stdio.h>
#include <stdlib.h>

int main() {
	int i = 2;
	int runs = 5;

	switch(i){
	case 0 :
		printf("DOT BALL");
	case 1 :
		printf("SINGLE");
	case 2 :
		printf("DOUBLE");
	case 3 :
		printf("TRIPLE");
	default :
		printf("FOUR OR A SIX");
	}
}

Can Switch be used around a character variable?

Yes. Switch can be done around int, long, short and also a char.