#include <iostream>
    #include <sstream>
    using namespace std;
    int main()
    {
        stringstream mys(ios :: in | ios :: out);
        std :: string dat("The double value is : 74.79 .");
        mys.str(dat);
        mys.seekg(-7, ios :: end);
        double val;
        mys >> val;
        val = val*val;
        mys.seekp(-7,ios::end);
        mys << val;
        std :: string new_val = mys.str();
        cout << new_val;
        return 0;
    }

    #include <iostream>
    using namespace std;
    class Base
    {
        public:
            Base(){}
            ~Base(){}
            protected:
            private: 
    };
    class Derived:public Base
    {
        public:
            Derived(){}
            Derived(){}
            private:
            protected:
    };
    int main()
    {
        cout << "The program exceuted" << endl;
    }

    #include <iostream>
    using namespace std;
    class MyException
    {
        public:
        MyException(int value) : mValue(value)
        {
        }
        int mValue;
    };
    class MyDerivedException : public MyException
    {
        public:
            MyDerivedException(int value, int anotherValue) : MyException(value),    mAnotherValue(anotherValue)
            {
            }
            int mValue;
            int mAnotherValue;
    };
    void doSomething()
    {
        throw MyDerivedException(10,20);
    }
    int main()
    {
        try
        {
            doSomething();
        }
        catch (MyDerivedException &exception)
        {
            cout << "\nCaught Derived Class Exception\n";
        }
        catch (MyException &exception)
        {
            cout << "\nCaught Base Class Exception\n";
        }
        return 0;
    }

    #include <iostream>
    #include <string>
    using namespace std;
    int main() 
    {
        string s = "a long string";
        s.insert(s.size() / 2, " * ");
        cout << s << endl;
        return 0;
    }