f string C#

// To use interpolation in strings, put the name of the relevant
// variable between brackets {} and put a dollar sign $ in front
// of the string. This will tell C# to use interpolation.
double a = 3;
double b = 4;
Console.WriteLine($"Area of {a} and {b} is {0.5 * a * b}");

string name = "John"
Console.WriteLine($"Hello {name}")