Question

The following method public String removeFromString(String old, String frag) removes all occurences of the string frag from the string old. For example, removeFromString("hello there!", "he") returns "llo tre!" removeFromString("lalalala", "l") returns "aaaa" Which of the following blocks of code will successfully implement removeFromString()?

Answer 1

private static String removeFromString(String old, String frag)

{

int i = old.indexOf(frag);

while (i> -1) {

String rest = old.substring(i + frag.length());

System.out.println("rest = " + rest);

old = old.substring(0, i);

System.out.println("rest = " + old);

old = old + rest;

System.out.println("rest = " + old);

i = old.indexOf(frag);

System.out.println("i = "+ i);

}

return old;

}

Here the index of first occurrence is obtained outside the “while loop” and if this loop runs until index value is >-1. It extracts the rest of the characters other than “frag” from the index and all the characters for which the given set of characters are removed.