Use the attached C program front.c  (compile it – see the instruction for using the c program,) and apply it to   (sum + 47) / total to get the following tokens Next token is: 25 Next lexeme is ( Next token is: 11 Next lexeme is sum Next token is: 21 Next lexeme is + Next token is: 10 Next lexeme is 47 Next token is: 26 Next lexeme is ) Next token is: 24 Next lexeme is / Next token is: 11 Next lexeme is total Next token is: -1 Next lexeme is EOF front.c：

Code: 

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.StringTokenizer;

/**
*
* @author prmsh
*/
public class Lexical {
public static void main(String args[]) throws FileNotFoundException{
//reading file
Scanner input = new Scanner(new File("C:\\Users\\prmsh\\Documents\\NetBeansProjects\\Chegg\\src\\chegg\\Expression.txt"));
while(input.hasNextLine()) {
//reading next line
String line = input.nextLine();
//reading tokens by space
StringTokenizer strings = new StringTokenizer(line," ");
//reading more strings
while (strings.hasMoreElements()) {
//converting object to string
String token = strings.nextElement().toString();
switch(token) //switch case
{
case "(" :
System.out.println("Next token is: 25 Next lexeme is (");
break;
case ")" :
System.out.println("Next token is: 26 Next lexeme is )");
break;
case "=" :
System.out.println("Next token is: 20 Next lexeme is =");
break;
case "+" :
System.out.println("Next token is: 21 Next lexeme is +");
break;
case "-" :
System.out.println("Next token is: 22 Next lexeme is -");
break;
case "*" :
System.out.println("Next token is: 23 Next lexeme is *");
break;
case "/" :
System.out.println("Next token is: 24 Next lexeme is /");
break;
default :
System.out.println("Next token is: 11 Next lexeme is "+token);
}
}
//finally end of the String
System.out.println("Next token is: -1 Next lexeme is EOF");
}
}
}