bnf of c switch statement
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The document defines the BNF grammar for C switch statements. It specifies the syntax rules for switch statements, expressions, integer expressions, statements lists, case lines, and default lines. An example switch statement is provided and its derivation using the grammar rules is shown.
![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>](https://image.slidesharecdn.com/switch-170919141803/85/bnf-of-c-switch-statement-1-320.jpg)
bnf of c switch statement
- 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>
- 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; }