//-------------------------------------------------
//
// Examples of string handling
//
// Simon Parsons
// April 18th 2007
//
//-------------------------------------------------

// Include C++ library definitions


#include <iostream> // For input and output
#include <string>   // To handle strings

using namespace std;

int main()
{

    // Variable definitions

    int countG = 0;

    string dna = "ggtataccggaatatagg"; // Note how we can define a string and
    string dna2 = "ttggaagg";          // Give it a value

    string::size_type len, pos;        // This is the right data type for an 
                                       // index into a string.

    // Printing a string

    cout << "Here we print the string dna" << endl;
    cout << dna << endl << endl;

    // Calculating the length of a string

    cout << "Now we give the length of dna in two ways" << endl;
    len = dna.length();
    cout << len << endl;

    len = dna.size();
    cout << len << endl << endl;

    // Another way to concatente two strings

    cout << "Next we concatenate two strings and print the result" << endl;

    dna2 += dna;
    cout << dna2 << endl << endl;

    // You can make an empty string

    cout << "We can make that string blank" << endl;
    dna2.clear();
    cout << dna2 << endl;
    cout << "Do you want to see that again?" << endl << endl;

    // You can find a string within a string

    cout << "Where is tata in the string dna?" << endl;
    pos = dna.find("tata", 0);
    cout << pos << endl;
    cout << "Where does it occur the second time?" << endl;
    pos = dna.find("tata", pos + 1);
    cout << pos << endl << endl;

    // Or a character in a string

    cout << "Where is the first c?" << endl;
    pos = dna.find('c', 0);
    cout << pos << endl << endl;

    // npos is what you get if you can't find what you are looking for

    cout << "What if we look for the string dog?" << endl;
    pos = dna.find("dog", 0);
    cout << pos << endl;
    cout << "Eh?" << endl;
    cout << dna.npos << endl << endl;

    // That gives you a way to keep searching through a string until the end

    cout << "How many gs are there?" << endl;
    pos = dna.find('g',0);
    while (pos != dna.npos)
    {
        countG++;
        pos = dna.find('g', pos + 1);
    }
    cout << countG << endl << endl;

    // Replace text
    
    cout << "Replace 4 characters starting in position 2 with gaga" << endl; 
    dna.replace(2, 4, "gaga");
    cout << dna <<endl;

    // Replace tata with gaga

    cout << "Replace tata with gaga" << endl; 
    dna.replace(dna.find("tata"), 4, "gaga");
    cout << dna <<endl;

    // Replace ggaa with tatatt

    cout << "Replace ggaa with tatatt" << endl; 
    pos = dna.find("ggaa");
    dna.erase(pos, 4);
    dna.insert(pos, "tatatt");
    cout << dna <<endl;

    return 0;
}