java - Find if Entered Password is valid or not? -

this interview question. think code below, works bit , has errors. problem follows -

in 1-9 keypad 1 key not working. if 1 enters password not working key not entered. have given expected password , entered password. check entered password valid or not ex: entered 164, expected 18684 (you need take care when u enter 18684 , 164 both taken 164 input)

the code above below.

public static void main(string[] args){         system.out.println(isamatch("164","18684"));       }      static boolean isamatch(string actual, string expected)     {         char faultykey = '\0';         int = 0, j = 0;         for(; < expected.length() && j < actual.length(); ++i)         {             if(actual.charat(j) != expected.charat(i))             {                 if('\0' != faultykey){                     if(faultykey != expected.charat(i))                         return false;                 }                 else{                     faultykey = expected.charat(i);                 }             }             else{                 ++j;             }         }         system.out.println("faultykey= "+faultykey);         return (i == expected.length() - 1 && j == actual.length() - 1)? true : false;     } 

it detecting faulty key correctly (ex here 8), giving wrong output (as false) though test case used above should give true. suggestions fix this? if better method/ideas appreciated.

static boolean isamatch(string actual, string expected) {         char faultykey = '\0';         int = 0, j = 0;         (; < expected.length(); ++i) {             if (j >= actual.length() || actual.charat(j) != expected.charat(i)) {                 if ('\0' != faultykey) {                     if (faultykey != expected.charat(i)) {                         return false;                     }                 } else {                     faultykey = expected.charat(i);                 }             } else {                 ++j;             }         }         system.out.println("faultykey= " + faultykey);         return (i == expected.length() && j == actual.length()) ? true : false;     } 

consider following condition

system.out.println(isamatch("164", "186848")); 

your logic not work, because before meets length j meet actual length. dont need have condition j < actual.length in loop.