C Programming - Switch statement - Interesting

This post demonstrates not well-known features of switch statement in any programming language that makes use of switch-case structure.

Switch Statement -

When the program encounters the situation to choose a particular statement among many statements, then the programmer decides to choose one block of statement depending on the problem statement.

This can be achieved with alternatives like if, if-else, nested if-else. But this makes no program readability and makes programming logic complex. So, this type of problem can be handled in C programming using switch statement.

Syntax -

switch(expression){
    case constant-expression  :
       statement(s);
       break; /* optional */
    case constant-expression  :
       statement(s);
       break; /* optional */
  
    /* you can have any number of case statements */
    default : /* Optional */
       statement(s);
}

 

Flowchart Representation -

 

   

Note – Consider every code block contains the break statement except the defaultcode block at the end.

break statement is optional.

break statement breaks the execution and exits the switch once the matched case statements are executed.

 

Not Well-Known Features -

A switch statement’s case labels can occur inside

• if-else statements
• loops (for, while)

Sample Code -

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

int main()
{
    int a,b;
    a=1;
    b=1;
    switch(a)
    {
        case 1: printf("Hello\n");

                if(b==2)
                {
                    case 2: printf("Printing the case statement from if\n");
                }
                else case 3:
                {
                    for(b=1;b<=10;b++)
                    {
                        case 5: printf("Printing the case statement from for loop\n");
                    }
                }

                break;

        case 4: printf("World\n");
                break;
    }       
return 0;

 

Output -

Hello
Printing the case statement from for loop
Printing the case statement from for loop
Printing the case statement from for loop
Printing the case statement from for loop
Printing the case statement from for loop
Printing the case statement from for loop
Printing the case statement from for loop
Printing the case statement from for loop
Printing the case statement from for loop
Printing the case statement from for loop

 

Summary -

It is 100% allowed to include if-else and loops inside the switch statement.

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Karthik Byggari

Author & Editor

Computer Science graduate, Techie, Founder of logicallyproven, Love to Share and Read About pprogramming related things.