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Java Java Objects Delivering the MVP Exceptions

Posted by hamdan hassan
hamdan hassan
Courses Plus Student 1,236 Points

can someone explain this

public boolean applyGuess(char letter){

    if(hits.indexOf(letter) != -1 || misses.indexOf(letter) != -1){

        throw new IllegalArgumentException(letter + " has already been guessed");

    }

   boolean isHit = answer.indexOf(letter) != -1;

   if(isHit)
       hits += letter;
   else
       misses += letter;

   return isHit;
}

1 Answer

Michael Clark
Michael Clark
16,324 Points
Michael Clark
Michael Clark
16,324 Points

Hi Hamdan

indexOf returns -1 if the specified character is not found in a string

if(hits.indexOf(letter) != -1 || misses.indexOf(letter) != -1){

        throw new IllegalArgumentException(letter + " has already been guessed");

    }

So with not equal (!=) this will return true if the character is in hits or misses and throw an exception that the letter has already been guessed.

Next isHit becomes true if the letter is in the answer or false otherwise

boolean isHit = answer.indexOf(letter) != -1;

The if statement then adds to hits if true and misses if false and returns isHit

if(isHit)
       hits += letter;
   else
       misses += letter;

   return isHit;