string stl functions.cpp

//append(): Inserts additional characters at the end of the string (can also be done using ‘+’ or ‘+=’ operator). Its time complexity is O(N) where N is the size of the new string.
//assign(): Assigns new string by replacing the previous value (can also be done using ‘=’ operator).
//at(): Returns the character at a particular position (can also be done using ‘[ ]’ operator). Its time complexity is O(1).
//begin(): Returns an iterator pointing to the first character. Its time complexity is O(1).
//clear(): Erases all the contents of the string and assign an empty string (“”) of length zero. Its time complexity is O(1).
//compare(): Compares the value of the string with the string passed in the parameter and returns an integer accordingly. Its time complexity is O(N + M) where N is the size of the first string and M is the size of the second string.
//copy(): Copies the substring of the string in the string passed as parameter and returns the number of characters copied. Its time complexity is O(N) where N is the size of the copied string.
//c_str(): Convert the string into C-style string (null terminated string) and returns the pointer to the C-style string. Its time complexity is O(1).
//empty(): Returns a boolean value, true if the string is empty and false if the string is not empty. Its time complexity is O(1).
//end(): Returns an iterator pointing to a position which is next to the last character. Its time complexity is O(1).
//erase(): Deletes a substring of the string. Its time complexity is O(N) where N is the size of the new string.
//find(): Searches the string and returns the first occurrence of the parameter in the string. Its time complexity is O(N) where N is the size of the string.
//insert(): Inserts additional characters into the string at a particular position. Its time complexity is O(N) where N is the size of the new string.
//length(): Returns the length of the string. Its time complexity is O(1).
//replace(): Replaces the particular portion of the string. Its time complexity is O(N) where N is size of the new string.
//resize(): Resize the string to the new length which can be less than or greater than the current length. Its time complexity is O(N) where N is the size of the new string.
//size(): Returns the length of the string. Its time complexity is O(1).
//substr(): Returns a string which is the copy of the substring. Its time complexity is O(N) where N is the size of the substring.
//back(): returns last char of string;