Output of C programs | Set 30 (Switch Case)

Interesting Problems of Switch statement in C/C++

1. Program 1 C

   #include <stdio.h>
   int main()
   {
       int num = 2;
       switch (num + 2)
       {
       case 1:
           printf("Case 1: ");
       case 2:
           printf("Case 2: ");
       case 3:
           printf("Case 3: ");
       default:
           printf("Default: ");
       }
       return 0;
   }
   

   Output:

   Default: 

   Explanation: In switch, an expression "num+2" where num value is 2 and after addition the expression result is 4. Since there is no case defined with value 4 the default case got executed.
2. Program 2 C

   #include<stdio.h>
   void main()
   {
       int movie = 1;
       switch (movie << (2 + movie))
       {
       default:
           printf(" Traffic");
       case 4:
           printf(" Sultan");
       case 5:
           printf(" Dangal");
       case 8:
           printf(" Bahubali");
       }
   }
   

   Output:

   Bahubali

   Explanation: We can write case statement in any order including the default case. That default case may be first case, last case or in between the any case in the switch case statement. The value of expression "movie << (2 + movie)" is 8.
3. Program 3 C

   #include<stdio.h>
   #define L 10
   void main()
   {
       auto a = 10;
       switch (a, a*2)
       {
       case L:
           printf("ABC");
           break;
   
       case L*2:
           printf("XYZ");
           break;
   
       case L*3:
           printf("PQR");
           break;
   
       default:
           printf("MNO");
   
       case L*4:
           printf("www");
           break;
       }
   }
   

   Output:

   XYZ

   Explanation: In C, comma is also operator with least precedence. So if x = (a, b); Then x = b Note: Case expression can be macro constant.
4. Program 4 C

   #include<stdio.h>
   void main()
   {
       switch(2)
       {
       case 1L:
           printf("No");
   
       case 2L:
           printf("%s","GEEKS");
           goto Love;
   
       case 3L:
           printf("Please");
   
       case 4L:Love:
           printf("FOR");
       }
   }
   

   Output:

   GEEKSFOR

   Explanation: It is possible to write label of goto statement in the case of switch case statement.