Consider the following method substringFound, which is intended to return true if a substring, key, is located at a specific index of the string phrase. Otherwise, it should return false.

public boolean substringFound (String phrase, String key, int index)

{

String part = phrase. substring (index, index + key. length ());

return part. equals (key);

}

Which of the following is the best precondition for index so that the method will return the appropriate result in all cases and a runtime error can be avoided?

A. 0 < = index < phrase. length ()

B. 0 < = index < key. length ()

C. 0 < = index < phrase. length () + key. length ()

D. 0 < = index < phrase. length () - key. length ()

E. 0 < = index < phrase. length () - index

Question

Computers and Technology

Lina Owens

26 September, 12:16

Consider the following method substringFound, which is intended to return true if a substring, key, is located at a specific index of the string phrase. Otherwise, it should return false.

public boolean substringFound (String phrase, String key, int index)

{

String part = phrase. substring (index, index + key. length ());

return part. equals (key);

}

Which of the following is the best precondition for index so that the method will return the appropriate result in all cases and a runtime error can be avoided?

A. 0 < = index < phrase. length ()

B. 0 < = index < key. length ()

C. 0 < = index < phrase. length () + key. length ()

D. 0 < = index < phrase. length () - key. length ()

E. 0 < = index < phrase. length () - index

+1

Answers (1)

Know the Answer?

Rudy Byrd · Answer 1

Option D 0 < = index < phrase. length () - key. length ()

Explanation:

The index has to be between the range of 0 < = index < phrase length - key length to prevent index out of bound error. This is because the substring method will have to extract part of the string with a certain length from the original string starting from the index-position. If the key length is longer than the string area between phrase[index] and phase. length (), an index out of bound runtime error will be thrown.