programming languages

1. BNF OF C-SWITCHSTATEMENT
<switch_stmnt>-> switch (<int_exp>) {<case_list>}
<int_exp> -> <int_exp>+ <exp> |
<int_exp>- <exp> |
<int_exp>& <exp>|
<int_exp>| <exp>|
<int_exp>>> <exp>|
<int_exp><< <exp>|
<exp>
<exp> -> <exp>* <term > |
<exp>/ <term> |
<term >
<term > -> (<int_exp>) |
<num_exp>|
- <term> |
^<term>
<num_exp> -> <int_id>|
<int_const>
<int_id> -> [a-zA-Z_] |
<int_id>[a-zA-Z0-9_]
<int_const> -> [0-9] |
<int_const> [0-9] |
- <int_const>
<case_list> -> <case_line>|
<case_line><case_list>|
<case_list><default_line>
<case_line> -> case <int_const>: <stmnt_list>
<default_line> -> default: <stmnt_list>
<stmnt_list> -> |
<stmnt> |
<stmnt> <stmnt_list>|
<stmnt_list>break;
<stmnt> -> statement<count>;
<count> -> [0-9] |
[0-9] <count>

2. Example:
intx;
switch(x)
{
case 1:
statement1;
break;
case 2:
statement2;
break;
default:
statement3;
}

3. Derivation:
<switch_stmnt>=>switch ( <int_exp> ) { <case_list> }
=>switch ( <exp> ) { <case_list> }
=>switch ( <term> ) { <case_list> }
=>switch ( <num_exp> ) { <case_list> }
=>switch ( <int_id> ) { <case_list> }
=>switch ( x ) { <case_list> }
=>switch ( x ) { <case_line><case_line><default_line> }
=>switch ( x ) { case <int_const>:<stmnt_list><case_line><default_line> }
=>switch ( x ) { case 1: <stmnt_list><case_line><default_line> }
=>switch ( x ) { case 1: <stmnt>break; <case_line><default_line> }
=>switch ( x ) { case 1: statement<count>;break; <case_line><default_line> }
=>switch ( x ) { case 1: statement1;break; <case_line><default_line> }
=>switch ( x ) { case 1: statement1;break; case <int_const>:<stmnt_list><default_line> }
=>switch ( x ) { case 1: statement1;break; case 2:<stmnt_list><default_line> }
=>switch ( x ) { case 1: statement1;break; case 2:<stmnt>break;<default_line> }
=>switch ( x ) { case 1: statement1;break; case 2:statement<count>;break;<default_line> }
=>switch ( x ) { case 1: statement1;break; case 2:statement2;break;<default_line> }
=>switch ( x ) { case 1: statement1;break; case 2:statement2;break;default:<stmnt_list }
=>switch ( x ) { case 1: statement1;break; case 2:statement2;break;default:<stmnt>}
=>switch ( x ) { case 1: statement1;break; case 2:statement2;break;default:statement<count>;}
=>switch ( x ) { case 1: statement1;break; case 2:statement2;break;default:statement3;}

5. Parse Tree:

6. Crazy example:
int a, b, c;
switch((a*b)+c)>>9)
{
case 0:
case 1:
statement 2;
break;
case 2:
statement3;
break;
default:
statement4;
statement5;
}