So, I am working on a project, and I have two files in this project: main.cpp, matrix.h

The problem is that My code seemed to work perfectly a few hours ago, and now it doesn't

main.cpp:

#include <iostream>
#include "matrix.h"
#include <vector>
int main() {
    Matrix f;
    f.create(10, 1, {3, 4, 5, 6, 7, 8, 9});
}

matrix.h:

#pragma once
#include <iostream>
#include <string>
#include <Windows.h>
#include <vector>
class Matrix {
public:
    const size_t N;
    bool ifMatrixCreated;
    const char* NOTENOUGH = "The size of the array should match to the width*height elements";
    std::vector<int> arr;
    int w, h;
    void create(int width, int height, const std::vector<int> a) {
        w = width;
        h = height;
        if (a.size() != width * height) {
            ifMatrixCreated = false;
            std::cout << "bello";
        }
        else {
            ifMatrixCreated = true;
            arr = a;
            std::cout << "hello";
        }
    }
};

And when I compile, it generates this error (Using VS2019):

Error   C2280 | 'Matrix::Matrix(void)': attempting to reference a deleted function  Matrix | Line 5

It keeps saying that "The default constructor of Matrix cannot be referenced - It is a deleted function"

Can you help solve this error?

Thanks in advance.

CodePudding user response：

Here is the correct working example. The error happens because every const data member must be initialized. And

The implicitly-declared or defaulted default constructor for class T is undefined (until C 11)defined as deleted (since C 11) if any of the following is true:

• T has a const member without user-defined default constructor or a brace-or-equal initializer (since C 11).

#pragma once
#include <iostream>
#include <string>
//#include <Windows.h>
#include <vector>
class Matrix {
public:
    //const size_t N;//this const data member must be initialised
    const size_t N = 6;
    bool ifMatrixCreated;
    const char* NOTENOUGH = "The size of the array should match to the width*height elements";
    std::vector<int> arr;
    int w, h;
    void create(int width, int height, const std::vector<int> a) {
        w = width;
        h = height;
        if (a.size() != width * height) {
            ifMatrixCreated = false;
            std::cout << "bello";
        }
        else {
            ifMatrixCreated = true;
            arr = a;
            std::cout << "hello";
        }
    }
};