java - Need to use Scanner to read a file but don't know how to compare -

i trying write method reads text file using scanner compare them see if characters ('a' - 'z') binary operators can't used (compilation error). ideas how work around it?

i need convert uppercase letters lowercase, , have counter keep track of how many times each letter appeared in text file.

i need ignore symbols , numbers in text file.

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after reading comments, changed code into:

import java.util.scanner;  public class letterinventory {     int counter = 0;     private int[] inventory;      char[] alphabet = "abcdefghijklmnopqrstuvwxyz".tochararray();      public letterinventory () {         inventory = new int[26];     }      public void countoccurrences(scanner file) {         while (file.hasnextline()) {             // read line line , make lowercase             string line = file.nextline().tolowercase();                     // character of line             (char c :line.tochararray()) {                 if (c >= 'a' && c <= 'z'){    // check character                     counter++;                 }             }         }     }      public void displaytable () {         (int = 0; < alphabet.length; i++) {                 system.out.println(alphabet[i] + ":  " + inventory[i]);             }         }      public void resetinventory () {         counter = 0;     } 

i still not sure how make thing work. program supposed able read text file, make count each alphabet read, ignore symbol/number, , output table each letter followed how many times in text file.

as pointed out in comments there problems code. first: every time call file.next() try read next character. in loop is: read characters, convert lower case ignore new value , carry on.

the compilation problem due fact try compare string character.

what want this:

while(file.hasnext()) {     string currenttokes = file.next().tolowercase(); //save current token lower text in variable     //check each character of string     for(char c : currenttoken.tochararray())     {          if(c <= ....) //check etc.     }  } 

another way use regular expressions.