43) How many parameters does a default constructor require? a. 1 b. 2 c. 0 d. 3

c. 0.

A default constructor is a constructor that can be called with no arguments. It is used to initialize the object's data members to default values. In C++, a default constructor can be defined without any parameters, like this:

class MyClass {
public:
    MyClass() {
        // constructor code here
    }
};

This constructor takes no parameters and initializes the object's data members to their default values.

相关问题

No primary or default constructor found for class com.bizsoft.winqframe.webtags.Grid.Searching

I'm sorry, but I cannot provide a solution to a specific code issue without more context or code details. However, I can provide some general guidance on the error message you mentioned.

The error message "No primary or default constructor found for class" typically occurs when you try to create an instance of a class that does not have a constructor or does not have a default constructor.

In your case, it seems that you are trying to create an instance of the class `com.bizsoft.winqframe.webtags.Grid.Searching`, but the class does not have a constructor or a default constructor.

To resolve this issue, you can try one of the following:

1. Add a constructor to the `Searching` class: You can add a constructor to the `Searching` class that takes the required parameters, or add a default constructor without any parameters. For example:

public class Searching {
    // constructor with parameters
    public Searching(String param1, int param2) {
        // constructor implementation
    }

    // default constructor
    public Searching() {
        // constructor implementation
    }
}

2. Modify the code that creates an instance of the `Searching` class: If you don't have access to modify the `Searching` class, you can check the code that tries to create an instance of the class and ensure that it is using a valid constructor. For example:

Searching searching = new Searching("param1", 123);  // using constructor with parameters

Please provide more information or code if you need further assistance with this issue.

No primary or default constructor found for interface java.util.function.Predicate

"Predicate" 是 Java 8 引入的一个函数式接口，它代表了一个可以接受一个对象并返回布尔值的函数，用于判断某个条件是否满足。当你试图创建 Predicate 对象时，如果没有显式提供构造函数（primary constructor），因为它是接口而不是类，所以 Java 编译器不会自动提供默认构造函数。

如果遇到 "No primary or default constructor found for interface java.util.function.Predicate" 这样的错误，通常是因为你需要明确地实例化一个 Predicate 实现，比如使用 Lambda 表达式：

Predicate<MyObject> predicate = myObject -> myObject.someProperty > someValue;

这里 `myObject.someProperty > someValue` 就是一个匿名内部类，充当了 Predicate 的实现。如果你尝试使用空构造函数创建，编译器会报错，因为 Predicate 接口没有定义这样的构造方式。