如何在main方法中调用构造函数？

I'm writing a code in which in its main method I create an object. But I don't know how to call its constructor. here is my code:

我正在编写一个代码,在其主要方法中我创建了一个对象。但我不知道如何调用它的构造函数。这是我的代码:

//This class calculate the greatest common divisor of two number 
import static java.lang.Math.min;
public class Calculate2
{
    private int num1,num2;
    public Calculate2(int num1 , int num2)
    {
        this.num1=num1;
        this.num2=num2;
    }
    public static void main(String[] args) 
    {
       Calculate2 gcd = new Calculate2();
       gcd.GCD();
    }
    public void GCD()
    {
        int min_num;
        int greatestcommondivisor=0;
        min_num = min(num1,num2);
        for(int commondivisor=1;commondivisor <= min_num;commondivisor++)
        {
           if(num1%commondivisor==0 &&  num2%commondivisor==0)
           {
               greatestcommondivisor=commondivisor;
           }
           commondivisor++;
        }
        System.out.println(greatestcommondivisor);
    }//End of the method gcd


}//End of the class calculate2

how should I call the constructor?

我该如何调用构造函数?

4 个解决方案

#1

Fact that you created your own constructor means that default one will not be added by compiler.

您创建自己的构造函数的事实意味着编译器不会添加默认构造函数。

Also your constructor looks like

你的构造函数也是如此
```
public Calculate2(int num1, int num2) {
}
```
which means it requires two int arguments, so you need to pass some int values to it like

这意味着它需要两个int参数,因此您需要将一些int值传递给它
```
new Calculate2(42,24);
```

#2

Constructors in a class are called right when we declare the object. Thus declare your object like this

当我们声明对象时,类中的构造函数被调用。这样声明你的对象

Calculate2 obj = new Calculate2(1,2);

#3

Your Constructor is parameteris constructor

您的构造函数是参数构造函数

  You must pass value to parameteris  Construcor
  You Can Call With differnt of type

  int i=10;
  int j=5;
  Calculate2 gcd = new Calculate2(i,j);

  new  Calculate2(10,20);

   Calculate2 gcd = new Calculate2(10,20);

    Calculate2 gcd;
    gcd = new Calculate2(15,20);

#4

A constructor shares the same name as the class, so when u create a new object (gcd) like below

构造函数与类共享相同的名称,因此当您创建一个新对象(gcd)时,如下所示

Calculate2 gcd = new Calculate2();

You have already called the default constructor of the class Calculate2

您已经调用了Calculate2类的默认构造函数

But since, you have declared a constructor with parameters:

但是,因为,您已经声明了一个带参数的构造函数:

public Calculate2(int num1 , int num2)

This means that the constructor of the class requires 2 parameters in it num1 and num2, so you have to call it like

这意味着该类的构造函数需要num1和num2中的2个参数,因此您必须将其称为

Calculate2 obj_gcd = new Calculate2(100,200);

#1

Fact that you created your own constructor means that default one will not be added by compiler.