#include<bits/stdc++.h>

using namespace std;

// 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.

int main(){

string s1("Hello");

cout<<s1<<endl;

s1.append("world");

cout<<s1<<endl;

s1.assign("Hello again");

cout<<s1<<endl;

cout<<s1.at(3)<<endl;

// cout<<s1.begin()<<endl;

s1.clear();

cout<<s1<<endl;

cout<<s1.compare("hello")<<endl;

// cout<<s1.copy("hello")<<endl;

}