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# include <stdio.h>
# include <string.h>
# include <ctype.h>
// ---------------
# define TOKEN_LENGTH 50
enum TokenType { UNRECOGNIZED, CHARACTER, DELIMITER, RESWORD, IDENT, NUM } ;
/* TokenType
DELIMITER
;
:
=
<
>
+
-
*
/
(
)
RESWORD
quit
*/
enum ResultType { ERROR, INT, BOOL } ;
int uTestNum ;
// ---------------
struct Token {
TokenType tokenType ;
char *str ;
} ;
struct NextToken {
bool exist ;
TokenType tokenType ;
char *str ;
} ;
// ---------------
Token GetToken() ;
bool IsDelimiter( char ch ) ;
NextToken Delimiter( Token token ) ;
// Command
int ScanWhiteSpace( char & ch ) ;
char *Char2Str( char ch ) ;
int ScanToEnter( char & ch ) ;
// --------------------
int main() {
scanf( "%d", & uTestNum ) ;
printf( "Program starts...\n" ) ;
printf( "> " ) ;
Token token = GetToken() ;
while ( strcmp( token.str, "quit" ) != 0 ) {
} // while
printf( "Program exits...\n" ) ;
return 0 ;
} // main()
// --------------------
Token GetToken() {
// TokenType { DELIMITER, RESWORD, IDENT, NUM }
static NextToken nextToken ; // CXX0017: Error: symbol "nextToken" not found
char ch ;
int scanNum = ScanWhiteSpace( ch ) ;
Token token ;
token.str = new char[TOKEN_LENGTH] ;
while ( scanNum != EOF ) {
if ( IsDelimiter( ch ) ) {
strcpy( token.str, Char2Str( ch ) ) ;
token.tokenType = DELIMITER ;
nextToken = Delimiter( token ) ;
return token ;
} // end if
/*
if ( IsResWord() ) {
} // end if
if ( IsIdent() ) {
} // end if
if ( IsNum() ) {
} // end if*/
else {
printf( "Unrecognized token with first char : '%c'\n", ch ) ;
scanNum = ScanToEnter( ch ) ;
} // end else
} // while
return token ;
} // GetToken()
// ----------
/*
DELIMITER
;
:
=
<
>
+
-
*
/
(
)
*/
bool IsDelimiter( char ch ) {
if ( ch == ';' || ch == ':' || ch == '=' || ch == '<' || ch == '>' || ch == '+' || ch == '-' || ch == '*'
|| ch == '/' || ch == '(' || ch == ')' ) {
return true ;
} // end if
else
return false ;
} // IsDelimiter()
// -----
NextToken Delimiter( Token token ) {
int scanNum ;
char ch ;
NextToken nextToken ;
nextToken.str = new char[TOKEN_LENGTH] ;
if ( token.str[0] == ':' ) {
scanNum = scanf( "%c", & ch ) ;
if ( ch == '=' ) { // ':=' legal
strcat( token.str, Char2Str( ch ) ) ;
} // end if
else { // ': ', ':+', ':+-*/', '::=', ':abc', ':123', ':quit' illegal
token.tokenType = UNRECOGNIZED ;
while ( scanNum != EOF && ch != '\t' ) {
scanNum = scanf( "%c", & ch ) ;
} // while
} // end else
nextToken.exist = false ;
return nextToken ;
} // end if
else if ( token.str[0] == '<' ) {
scanNum = scanf( "%c", & ch ) ;
if ( scanNum == EOF || ch == ' ' || ch == '\n' || ch == '\t' ) { // '< '
nextToken.exist = false ;
return nextToken ;
} // end if
else if ( ch == '>' ) { // '<>'
strcat( token.str, Char2Str( ch ) ) ;
nextToken.exist = false ;
return nextToken ;
} // end else if
else if ( ch == '=' ) { // '<='
strcat( token.str, Char2Str( ch ) ) ;
nextToken.exist = false ;
return nextToken ;
} // end else if
else {
if ( IsDelimiter( ch ) ) { // '<+', '<-123', '<+-*/', '<:>'
nextToken.tokenType = DELIMITER ;
} // end if
else if ( isdigit( ch ) ) { // '<123'
nextToken.tokenType = NUM ;
} // end else if
else { // '<abc', '<q', '<quit'
nextToken.tokenType = CHARACTER ;
} // end else
nextToken.exist = true ;
strcpy( nextToken.str, Char2Str( ch ) ) ;
return nextToken ;
} // end else
} // end else if
else if ( token.str[0] == '>' ) {
return nextToken ;
} // end else if
else { // ( token.str[0] == ';' || token.str[0] == '=' || token.str[0] == '+' || token.str[0] == '-'
// || token.str[0] == '*' || token.str[0] == '/' || token.str[0] == '(' || token.str[0] == ')' )
nextToken.exist = false ;
return nextToken ;
} // end else
} // Delimiter()
// --------------------
int ScanWhiteSpace( char & ch ) {
int num = EOF ;
num = scanf( "%c", & ch ) ;
if ( num == EOF )
return num ;
while ( num != EOF &&
( ch == ' ' || ch == '\n' || ch == '\t' ) ) {
num = scanf( "%c", & ch ) ;
} // while
return num ;
} // ScanWhiteSpace()
// -----
char *Char2Str( char ch ) {
char *str = new char[2] ;
sprintf( str, "%c", ch ) ;
return str ;
} // Char2Str()
// -----
int ScanToEnter( char & ch ) {
int num = scanf( "%c", & ch ) ;
while ( num != EOF && ch != '\n' ) {
num = scanf( "%c", & ch ) ;
} // while
return num ;
} // scanToEnter()
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