Objects placed inside classes to be rendered with OpenGL

I began to learn OpenGL about a week ago and I now want to create a mesh class. The code I'm about to show gives me a black screen (that's the color I fill it with).

I basically stripped the code from my main function and placed it inside a class, it worked inside main.

mesh.cpp

    #include "mesh.h"

mesh::mesh(std::vector<GLfloat> vertices, std::vector<GLuint> triangles)
{
    this->vertices = vertices;
    this->triangles = triangles;
    glGenVertexArrays(1, &this->vertexArrayObject);
    glBindVertexArray(this->vertexArrayObject);

    glGenBuffers(1, &this->vertexBuffer);
    glGenBuffers(1, &this->triangleBuffer);

    glBindBuffer(GL_ARRAY_BUFFER, this->vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, this->vertices.size() * sizeof(GLfloat), this->vertices.data(), GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->triangleBuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, this->triangles.size() * sizeof(GLfloat), this->triangles.data(), GL_STATIC_DRAW);

    //ctor
}

mesh::~mesh()
{
    glDeleteBuffers(1, &this->triangleBuffer);
    glDeleteBuffers(1, &this->vertexBuffer);

    glDeleteVertexArrays(1, &this->vertexArrayObject);
    //dtor
}

void mesh::update(){
    glBindVertexArray(this->vertexArrayObject);
    glDrawElements(GL_TRIANGLES, this->vertices.size(), GL_UNSIGNED_INT, 0);
}

mesh.h

    #ifndef MESH_H
#define MESH_H

#include <iostream>
#include <vector>
#include <GL/glew.h>
#include <glm/glm.hpp>

class mesh
{
    public:
        mesh(std::vector<GLfloat> vertices, std::vector<GLuint> triangles);
        ~mesh();
        void update();
    protected:
    private:
        GLuint vertexArrayObject, vertexBuffer, triangleBuffer;
        std::vector<GLfloat> vertices;
        std::vector<GLuint> triangles;
};

#endif // MESH_H