Length of the String without using length() method [closed]

Answer 1

Since nobody's posted the naughty back door way yet:

public int getLength(String arg) {
  Field count = String.class.getDeclaredField("count");
  count.setAccessible(true); //may throw security exception in "real" environment
  return count.getInt(arg);
}

;)

Answer 2

This is a complete program you can compile and run it.

import java.util.Scanner;

class Strlen{

    public static void main(String...args){
        Scanner sc = new Scanner(System.in);
        System.out.print("\nEnter Your Name =>" +"  ");
        String ab = sc.nextLine();
        System.out.println("\nName Length is:" +len(ab));
    }

    public static int len(String ab){
        char[] ac = ab.toCharArray();
        int i = 0, k = 0;

        try{
            for(i=0,k=0;ac[i]!='\0';i++)
                k++;
        }
        catch(Exception e){
        }
        return k;
    }

}

Answer 3

Just for completeness (and this is not at all recommended):

int length;
try
{
   length = str.getBytes("UTF-16BE").length / 2
}
catch (UnsupportedEncodingException e)
{
   throw new AssertionError("Cannot happen: UTF-16BE is always a supported encoding");
}

This works because a char is a UTF-16 code unit, and str.length() returns the number of such code units. Each UTF-16 code unit takes up 2 bytes, so we divide by 2. Additionally, there is no byte order mark written with UTF-16BE.

Answer 4

We can iterate through the string like a character array, and count that way (A much more down to earth way of doing it):

String s = "foo"
char arr[]=s.toCharArray();
int len = 0;
for(char single : arr){
  len++;
}

Using the "foreach" version of the for loop

Answer 5

Here's another way:

int length = 0;
while (!str.equals("")) {
    str = str.substring(1);
    ++length;
}

In the same spirit (although much less efficient):

String regex = "(?s)";
int length = 0;
while (!str.matches(regex)) {
    regex += ".";
    ++length;
}

Or even:

int length = 0;
while (!str.matches("(?s).{" + length + "}")) {
    ++length;
}

Answer 6

Even more slower one

public int slowerLength(String myString) {
String[] str = myString.split("");
int lol=0;
for(String s:str){
    lol++;
}
return (lol-1)
}

Or even slower,

public int slowerLength(String myString) {
String[] str = myString.split("");
int lol=0;
for(String s:str){
    lol += s.toCharArray().length;
}
return lol
}