Programming Discrete Math Concepts for Beginners/

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Interactions between Objects

Interactions between Objects

Learn how objects work with each other.

We'll cover the following...

Before discussing data structures, we must know how objects work with one another and how different objects pass messages between themselves. We’ll also try to insert data into a linked list manually. This is a list of elements connected with a link.

We’ll use four easy-to-understand sample Dart programs to see how one object works with other objects. Let’s talk about the first program. Suppose we have a group of people, and each person acquires a mobile application that helps them to enter their tasks. They can categorize the tasks, and according to the necessity, they finish their tasks.

Code for multiple classes

To accomplish this task, we need to have two classes—Person and the mobile application (AppToDo) class. We need an application object inside the Person class because one person object acquires one application object. The application object has a blueprint or class that defines what it can and can’t do.

Let’s code the two classes. Once a person acquires an application object, they can start doing everything defined in the mobile application class with that object.

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//Dart
void main(){
    var appOne= AppToDo("AppToDoOne");
    var appTwo= AppToDo("AppToDoTwo");
    var john= Person("John");
    var mac= Person("Mac");
    john.taskToDo= appOne;
    mac.taskToDo= appTwo;
    print("${john.name} gets ${john.taskToDo.name}.");
    print("${mac.name} gets ${mac.taskToDo.name}.");
    /*
    John gets AppToDo One.
    Mac gets AppToDo Two
    */
    print("${john.name} is entering tasks.");
    john.taskToDo.task="Going to the market to get some vegetables";
    john.taskToDo.type="Marketing";
    john.taskToDo.enterTask();
    //we presume that every task is important
    john.getTaskFinished(appOne);
    print("${mac.name} is entering tasks.");
    mac.taskToDo.task="Going out with friends";
    mac.taskToDo.type="Outing";
    mac.taskToDo.enterTask();
    //in some cases, the task may not be so important
    appTwo.isImportant= false;
    mac.getTaskFinished(appTwo);
}
class AppToDo{
    String name;
    String task;
    String type;
    bool isImportant=true;
    AppToDo(Stringname){
        this.name = name;
    }
    void enterTask(){
        print("I want to finish this task - ${task}. It belongs to this type - ${type}.");
    }
}
class Person{
    String name;
    AppToDo taskToDo;
    Person(String name){
        this.name = name;
    }
    void getTaskFinished(AppToDo taskToDo){
        this.taskToDo = taskToDo;
        if(taskToDo.isImportant){
            print("This task - ${taskToDo.task} is important and needs to be finished.");
        } else {
            print("It can be avoided; it is not so important");
        }
    }
}

Each person object is a separate entity, and each application object is a separate entity. However, all separate objects have some commonalities that are defined in the class.

We can expect the following output:

John gets null.
Mac gets
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