conversion error

[cyter]

Why am I getting this error when I compile code?

error: conversion from 'rectangle*' to non-scalar type 'rectangle' requested

my class is in a header file named rectangle.h

#ifndef RECTANGLE_H
#define RECTANGLE_H
#include <cmath>
class rectangle
{
    private:
        int length,width;
    public:
        rectangle(int x,int y);
        virtual ~rectangle();
    int area()
    {   int a = length * width;
        return a;
    }
    int perimeter()
    {   int b = 2*(length * width);
        return b;
    }
    }
    int diagonal()
    {   int c= sqrt(length * width);
        return c;
    }
};
#endif // RECTANGLE_H 

here's my main function

#include <iostream>
#include "rectangle.h"
using namespace std;

int main()
{
    rectangle rect = new rectangle(3,4);

    cout<<rect.area()<<endl;

    cout<<rect.perimeter()<<endl;

    return 0;
}

[EwCjE3v7]

Made a few changes to fix it.

#ifndef RECTANGLE_H
#define RECTANGLE_H
#include <cmath>
class rectangle
{
    private:
        int length,width;
    public:
        rectangle() = default; // this is needed
        rectangle(int x,int y) : length(x), width(y) {} // changed
        // removed virtual ~rectangle();
    int area()
    {   int a = length * width;
        return a;
    }
    int perimeter()
    {   int b = 2*(length * width);
        return b;
    }
    // removed '}'
    int diagonal()
    {   int c= sqrt(length * width);
        return c;
    }
};
#endif // RECTANGLE_H  

[Peter87]

Change rectangle rect = new rectangle(3,4); to rectangle rect(3,4);

[48T7M4Gy]

Another way is to recognise that new generates a pointer so:

	rectangle* rect = new rectangle(3, 4);
	cout << rect->area() << endl;
	cout << rect->perimeter() << endl;

[cyter]

Thank you kemort.