Java Lexical Analyzer -


i'm creating lexical analyzer. in code can output symbols, when comes letters , numbers cant design code in that..

please me in project.. thanks

package lab7;  import java.util.scanner; import java.util.stringtokenizer;  public class lab7 { public static void main(string[] args) {                 string word;         char[] wordarray;          scanner sc = new scanner(system.in);          wordarray = word.tochararray();          for(int x = 0; x < wordarray.length; x++) {              if(wordarray[x] == '+') {                 system.out.print("add ");             }             else if(wordarray[x] == '-') {                 system.out.print("subtract ");             }             else if(wordarray[x] == '*') {                 system.out.print("multiply ");             }             else if(wordarray[x] == '/') {                 system.out.print("divide ");             }             else if(wordarray[x] == '(') {                 system.out.print("math ");             }             else if(wordarray[x] == ')') {                 system.out.print("math ");             }             else if(wordarray[x] == '=') {                 system.out.print("assign ");             }          }     } }

character methods character.isletter , character.isdigit may here.

however can't write real lexical analyzer scanning string letter letter. lexical analyzer produces multi-character tokens , implemented state machine, defined regular expressions.

automatic splitting isn't useful here. example, if you'll split input string whitespaces, 12+34 single token. should define rules, example, read digits, while there digits, , on.. leads idea of ​​a finite automaton (or state machine).


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