Principle of least astonishment

A [[component]] of a system should behave in a manner consistent with how users of that component are likely expect it to behave.

Following principles and techniques are based on the principle of least astonishment: - [[Fault-Safe API]] - Command Query Separation Principle - [[Immutability]] - [[Design by Contract]]

Works fine:

reporting.PrintReportA();
reporting.PrintReportB();

Fails in runtime. Astonishment.

reporting.PrintReportB();
reporting.PrintReportA();

Java stack exposes: - [[Push]] - [[Pop]] - Add - Where the item will be added?

var array = new string[10];
var list = array as IList<string>; // this works
list.Add("foo"); // exception saying it's not supported