/* This program demonstrates
 * 1. Arrays of c-strings
 * 2. C++ string objects
 * 
 * An array of chars is a C-String. We can treat it as a regular array
 * along with all the special properties that apply to C-strings alone
 * Naturally, we can extend this idea into an array of C-Strings, which is
 * an array of arrays of chars - a 2 dimensional array of chars.
 * Here, each array of chars (an entire row of the array) can be treated as
 * a CString. Then, we only need to specify the row for the array.
 * We can also refer to each character individually. Then, we need to specify
 * both the row and the column.
 *
 * C++ offers a string class that makes it easier to work with strings.
 * The string class let's us use "string" as a user defined composite data
 * type. We can create variables of type string.
 * The biggest advantage of the string class is memory management. We do not
 * have to check for bounds. C++ handles resizing the array for us.
 * Internally a string object is still a CString, but C++ has just provided
 * us with tools to make it easier for us.
 * Here, we will demonstrate the 4 CString functions we learned about, using
 * C++ string objects.
 * To copy, we use the = sign instead of the strcpy function.
 * To get the length, we use the size function or length function instead of strlen
 * To concatenate, we use the += operator or the append function instead of strcat
 * To compare, we can just use the relational operators (<, <=, >, >=, ==, !=)
 * instead of strcmp. Comparison is still done in lexicographic order, but
 * it is easier to read.
 */

#include<iostream>
#include<cstring>
#include<string>

using namespace std;

void sort(char st[][100], int num);

int sentenceCount(string str);

int main()
{
    /* An array of C-strings is essentially a two dimensional array of chars, where
     * each "row" can be considered a CString on its own.
     */
    char names[10][100];

    cout<<"Enter 10 names: ";
    for(int i=0; i<10; i++)
        cin.getline(names[i], 100);

    sort(names, 10);

    cout<<"The sorted names are: "<<endl;
    for(int i=0; i<10; i++)
        cout<<names[i]<<endl;


    /* C++ defines "string" as the user-defined data type for a c++ string object
     * As we can see, we can use the same syntax we are used to with the numeric
     * data types.
     */
    string st1 = "Hello World";

    cout<<"st1: "<<st1;

    /* cin>> would work on a string object, but it would only read until the first whitespace.
    * We should use getline to read in a multi-word string.
    * The syntax for getline is slightly different for string objects.
    * We start off with getline, move the cin inside as a parameter, and
    * pass in the string variable and the terminating character.
    * We leave out the size because C++ handles the size for us.
    * As usual, the terminating character is aby default, the newline,
    * We need a cin.ignore() between a non-getline input and a getline input.
    */
    cout<<"Enter some text: ";
    getline(cin, st1, '\n');

    cout<<"You entered: "<<st1<<endl;

    /* Size and Capacity
     * The capacity of a string is the amount of space allocated for the string
     * It is the maximum number of characters the string is capable of holding.
     * The size (or length) of the string is the number of characters in the
     * string right now.
     */

    cout<<"String length: "<< st1.size() <<endl;
    cout<<"String length: "<< st1.length()<< endl;
    cout<<"String capacity: "<< st1.capacity() <<endl;

    /* string is a class, so it contains functions that can act upon the
     * variables of the string type.
     * The syntax for these functions is: variable.function()
     * This is demonstrated above, when we called size and capacity
     */

    string copy;
    cout<<"Enter copy string: ";
    getline(cin, copy);

    cout<<"You entered: "<< copy<<endl;

    copy = st1;    // use = instead of strcpy(), copy using assignment
    cout<<"copy is now "<< copy<<endl;
    cout<<"capacity of copy: "<<copy.capacity()<<endl;


    st1 = st1 + " More text here";      // use + instead of strcat, concatenate using +
    cout<<"st1: "<<st1<<endl;

    string st2;
    cout<<"Enter 2 strings: ";
    getline(cin, st1);
    getline(cin, st2);

    //use relational operators instead of strcmp()

    if(st1 < st2)
        cout<<st1<< " was the leeser string"<<endl;
    else if (st1 > st2)
        cout<<st2<<" was the lesser string"<<endl;
    else cout<<"The two strings are equal"<<endl;

    cout<<"The number of sentences: "<< sentenceCount(st1)<<endl;
    return 0;
}

/* sort function
 * Same algorithm as naive bubble sort we used for integers
 * We use strcmp instead of relational operators and strcpy instead of = to copy
 */
void sort(char arr[][100], int size)
{
    char temp[100];
    for(int i=0; i< size-1; i++)
    {
        for(int j=0; j< size -1 - i; j++)
        {
            if( strcmp(arr[j], arr[j+1]) > 0)
            {
                strcpy(temp, arr[j]);
                strcpy(arr[j], arr[j+1]);
                strcpy(arr[j+1],temp);
            }
        }
    }
}

/* We can index into the internal c-string of a c++ string object using the
 * index-of operator [].
 * This part works just like a C-string
 * This is the sentenceCount function we wrote for a C-string, adapted for
 * C++ string objects.
 */
int sentenceCount(string st)
{
    int count = 0;
    for(int i=0; i< st. size(); i++)
    {
        if( st[i] =='.' || st[i] =='?' || st[i] =='!')
            count++;
    }
    return count;
}