Largest Word In a Sentence

import java.io.*;
class MyString
{
int len;String str;
MyString()
{
len=0;str=null;
}
void ReadString()throws IOException
{
BufferedReader x=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter a sentence");
str=x.readLine ();
}
int code(int index)
{
int p=str.charAt(index);
return p;
}
void word()
{
str=str.trim();str=str+" ";len=str.length();
int c=0,i=0;
String w="",largest="";
for(i=0;i<len-1;i++)
{
if(str.charAt(i)!=' '&&str.charAt(i+1)==' ')
++c;
}
String a[]=new String[c];
i=0;
do
{
a[i]=str.substring(0,str.indexOf(' '));
str=str.substring (str.indexOf(' '),str.lastIndexOf(' '));
str=str.trim();
str=str+" ";
++i;
}
while(str.compareTo(" ")!=0);
int l=a[0].length();
for(i=0;i<c;i++)
{
if(a[i].length()>l)
{
l=a[i].length();
largest=a[i];
}
}
System.out.println("Largest word="+largest);
}
}