Remarks. Example using System; // Define an DayOfWeek data type enum DayOfWeek { Sunday, Monday

Пример

Example

using System; // Define an DayOfWeek data type enum DayOfWeek { Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday }; // Define a struct to store the methods and operators struct Day { private DayOfWeek day; // The constructor for the struct public Day(DayOfWeek initialDay) { day = initialDay; } // The overloaded + operator public static Day operator +(Day lhs, int rhs) { int intDay = (int)lhs.day; return new Day((DayOfWeek)((intDay + rhs) % 7)); } // An overloaded ToString method public override string ToString() { return day.ToString(); } } public class Program { static void Main() { // Create a new Days object called "today" Day today = new Day(DayOfWeek.Sunday); Console.WriteLine(today.ToString());   today = today + 1; Console.WriteLine(today.ToString());   today = today + 14; Console.WriteLine(today.ToString()); } }

using System;

// Define an DayOfWeek data type

enum DayOfWeek { Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday };

// Define a struct to store the methods and operators

struct Day

{

private DayOfWeek day;

// The constructor for the struct

public Day(DayOfWeek initialDay)

{

day = initialDay;

}

// The overloaded + operator

public static Day operator +(Day lhs, int rhs)

{

int intDay = (int)lhs.day;

return new Day((DayOfWeek)((intDay + rhs) % 7));

}

// An overloaded ToString method

public override string ToString()

{

return day.ToString();

}

}

public class Program

{

static void Main()

{

// Create a new Days object called "today"

Day today = new Day(DayOfWeek.Sunday);

Console.WriteLine(today.ToString());

today = today + 1;

Console.WriteLine(today.ToString());

today = today + 14;

Console.WriteLine(today.ToString());

}

}

Decisions and Branching

Changing the flow of control in a program in response to some kind of input or calculated value is an essential part of a programming language. C# provides the ability to change the flow of control, either unconditionally, by jumping to a new location in the code, or conditionally, by performing a test.

The simplest form of conditional branching uses the if construct. You can use an else clause with the if construct, and if constructs can be nested.

using System; class Program { static void Main() { int x = 1; int y = 1; if (x == 1) Console.WriteLine("x == 1"); else Console.WriteLine("x!= 1"); if (x == 1) { if (y == 2) { Console.WriteLine("x == 1 and y == 2"); } else { Console.WriteLine("x == 1 and y!= 2"); } } } } Note: Unlike C and C++, if statements require Boolean values. For example, it is not permissible to have a statement that doesn't get evaluated to a simple True or False, such as (a=10). In C#, 0 cannot be substituted for False and 1, or any other value, for True.

Дата добавления: 2014-12-27