interface ICalculate
{
//Property signature
int a
{
get;
set;
}
int b
{
get;
set;
}

//method signature
int Sum();
}

//Look at the derived class
class Calculate : ICalculate
{
#region Member Variable
int iA = 0;
int iB = 0;
#endregion

#region ICalculate Members

public int a
{
get
{
return iA;
}
set
{
iA = value;
}
}

public int b
{
get
{
return iB;
}
set
{
iB = value;
}
}

public int Sum()
{
return a + b;
}

#endregion
}