lex yacc tutorial by Tom Niemann

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KTU Compiler Lab CSL411 - Dr Binu V P

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lexical analyzer for a c program

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 This program identifies tokens in a C program ignoring white spaces and comments.The input C program is given as argument ******************************* %{ #include <stdio.h> %} %option noyywrap /* Define regular expressions for different token types */ DIGIT      [0-9] LETTER     [a-zA-Z] IDENTIFIER {LETTER}({LETTER}|{DIGIT})* NUMBER     {DIGIT}+ WHITESPACE [ \t\n]+ COMMENT1    "//".* COMMENT2  "/*"([^*]|\*+[^/*])*\*+"/" %% {WHITESPACE}        { /* Ignore whitespace */ } {COMMENT1}           { /* Ignore comments */ } {COMMENT2}           { /* Ignore comments */ } "int"               { printf("TOKEN_INT\n"); } "return"            { printf("TOKEN_RETURN\n"); } "if"                { printf("TOKEN_IF\n"); } "else"    ...
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