C++ Programming

Questions

1. What are Virtual Tables?
2. What is const-correctness?

Snippet 1

#include<iostream>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<algorithm>

using namespace std;

class CLASSNAME {
    public:
        // method name
        int foo()
        {
            return 0;
        }
};

int main(int argc, char *argv[])
{
    CLASSNAME obj;
}

Snippet 2

#include <iostream>
#include <ostream>
#include <limits>

using namespace std;

int main()
{

    typedef std::numeric_limits< double > dl;
    typedef std::numeric_limits< float > fl;

    cout << "double:\n";
    cout << "\tdigits (bits):\t\t" << dl::digits << endl;
    cout << "\tdigits (decimal):\t" << dl::digits10 << endl;

    cout << endl;

    cout << "float:\n";
    cout << "\tdigits (bits):\t\t" << fl::digits << endl;
    cout << "\tdigits (decimal):\t" << fl::digits10 << endl;

}

Snippet 3

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> ii;

#define sz(a) int((a).size())
#define pb push_back
#define all(c) (c).begin(),(c).end()
#define tr(c,i) for(typeof((c).begin() i = (c).begin(); i != (c).end(); i++)
#define present(c,x) ((c).find(x) != (c).end())
#define cpresent(c,x) (find(all(c),x) != (c).end())
#define all(c) c.begin(), c.end()
#define tr(container, it) \
    for(typeof(container.begin()) it = container.begin(); it != container.end(); it++)

#include<map>
#include<iostream>

using namespace std;

int main(int argc, char *argv[])
{
    map<int, int> m1;
    m1[1] = 100;
    m1[2] = 200;
    m1[3] = 300;
    tr(m1,it)
        cout<<it->first<<" "<<it->second<<endl;
}

Snippet 4

#include<map>
#include<iostream>

#define tr(container, it) \
    for(typeof(container.begin()) it = container.begin(); it !=container.end(); it++)
using namespace std;

int main(int argc, char *argv[])
{
    map<int, int> m1;
    m1[1] = 100;
    m1[2] = 200;
    m1[3] = 300;
    tr(m1,it)
        cout<<it->first<<" "<<it->second<<endl;
}

Snippet 5

#include<iostream>
#include<map>
#include<string>

using namespace std;

int main(int argc, char *argv[])
{
    map<int,int> mymap;
    map<string,string> mystrmap;
    mymap[10] = 100;
    mystrmap["senthil"] = "kumaran";
    cout<<mymap[10]<<endl;
    cout<<mystrmap["senthil"]<<endl;
}

Snippet 6

#include <vector>
#include <string>
#include <iostream>

using namespace std;

class StringBuilder {
    public:
        string buildString(vector<char> array)
        {
            // create a string for vector
            string s;

            // loop over every element in the array.

            for (int i = 0; i < array.size(); i++)
            {
                s = s + array[i];
            }

            return s;
        }
};

int main() {
    StringBuilder myStr;
    vector<char> myvect(10);
    for (int i=0; i < myvect.size(); i++) {
        myvect[i] = i;
    }
    cout << myStr.buildString(myvect);
    return 0;
}

Snippet 7

#include<vector>
#include<iostream>

using namespace std;

class Something
{
    public:
        int foo()
        {
            return 10;
        }
        int bar()
        {
            return foo();
        }
};

int main(int argc, char *argv[])
{
    vector <pair <int, int> > cords;
    cords.push_back(make_pair(1,-1));
    cords.push_back(make_pair(0,-1));
    int i;
    for (i =0; i < cords.size(); i++)
        cout<<cords[i].first<<" "<<cords[i].second<<endl;
    Something obj;
    cout<<obj.bar();
}