Help me correct the function and my void keep function below :

IMPORTANT DETAIL: Your implementation of LastN may not store more than nToKeep Strings. You CANNOT store every Stringpassed to keep(). Points will be deducted if you use more memory than necessary. Assume that a LastN object may be asked to keep only the last 10 of a million strings.

public class LastN { int nToKeep=0; Stack stack = new Stack(); LastN(int nToKeep) { this.nToKeep = nToKeep; }

void keep(String s) { stack.push(s); }

String[] getLastN() { String[] str = new String[nToKeep]; for(int i=nToKeep - 1 ; i>=0 ;i--) { str[i] = stack.pop(); } return str; }

public static void main (String[] args) { LastN ln = new LastN(3); ln.keep("one"); ln.keep("two"); ln.keep("three"); ln.keep("four"); ln.keep("five"); String[] last = ln.getLastN(); for(int i=0;i

My Input : one

two

The Output I got is :

Exception in thread "main" java.util.NoSuchElementException: Stack underflow

at Stack.pop(Stack.java:104)

at LastN.getLastN(LastN.java:20)

at TestLastN.zyBooksTest(TestLastN.java:75)

at TestLastN.main(TestLastN.java:97)

The correct out put should be : one

two