UML Learning: The dependency relationship of Class diagram classes

The concepts and symbols of dependency relations

dependencies represent a class that relies on other classes in some way. When two classes are in a dependency relationship, the change of one of the classes may affect another class.

Symbol:

The performance of dependencies in code

In program code, a dependency means that an object of one class appears in the operation of another class. There are two common scenarios in which a class takes an object of another class as an argument for an action of its own (a formal parameter) or a local variable of an operation.

Program Demo: Code/train

Class train
    {public
        string number;
    
        Public train (String num)
        {number
            = num;
        }
    
        public void Run ()
        {
            Console.WriteLine ("Train start ...) Train arrives ");
        }
    
Train

 class Person {public string name;
        Public person (string name) {this.name=name; public void gotobeijing (train mytrain)//from Henan to Beijing {Console.Write (name+ "Go to Beijing to ride {0} train:", MyTrain.
            number);
        Mytrain.run (); 
            public void Gotohenan ()//from Beijing to Henan {train mytrain = new Train ("1488");
            Console.Write (name + "Go to Henan ride {0} train:", Mytrain.number);
        Mytrain.run (); } person 

Class program
    {
        static void Main (string[] args)
        {person
            person1 = new Person ("John");
            Person Person2 = new Person ("Dick");
    
            Train train1 = new Train ("1487 times"); Henan to Beijing
        train train2 = new Train ("1488 times");//Henan to Beijing
        Person1. Gotobeijing (train1);
            Person2. Gotobeijing (train2);
            Person1. Gotohenan ();
            Person2. Gotohenan ();
        }
    
Program

The corresponding class diagram:

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