String III Capacity

size_t size() const;      //Returns a count of the number of characters in the string.

size_t length() const;    //Returns a count of the number of characters in the string.

size_t max_size ( ) const;
//Returns the maximum number of characters that the  object can hold.

void resize ( size_t n, char c );
void resize ( size_t n );
/*
Resizes the string content to n characters.If n is smaller than the current length of the string, the content is reduced to its first n characters, the rest being dropped.If n is greater than the current length of the string, the content is expanded by appending as many instances of the c character as needed to reach a size of n characters.The second version, actually calls: resize(n,char()), so when a string is resized to a greater size without passing a second argument, the new character positions are filled with the default value of a char, which is the null character.
*/

size_t capacity ( ) const; //Returns the size of the allocated storage space in the  object.

void reserve ( size_t res_arg=0 );
//Requests that the  of the allocated storage space in the string be at least res_arg.

void clear();
//The string content is set to an empty string, erasing any previous content and thus leaving its  at 0 characters.

bool empty ( ) const; //Returns whether the  is empty

#include <iostream>
#include <string>
using namespace std;

int
main(void)
{
        size_t sz;
        string str ("Hello");
        cout << "size: " << str.size() << endl;
        cout << "length: " << str.length() << endl;
        cout << "max_size: " << str.max_size() << endl;
        cout << "capacity: " << str.capacity() << endl;

        sz = str.size();
        str.resize(sz+2,'++');
        cout << str << endl;

        str.resize(3);
        cout << str << endl;

        str.clear();
        cout << str << endl;

        if (str.empty()) {
                cout << "The string is empty now" << endl;
        }

        return (0);
}