The code compiles ok:

#include <iostream>
#define GLEW_STATIC
#include <GL/glew.h>
#include <GLFW/glfw3.h>

const GLuint WIDTH = 800, HEIGHT = 600;

const GLchar* vertexShaderSource = "Version 330 coren"

                                   "layout (location = 0) in vec3 position;n"
                                   "void main()n"
                                   "{n"
                                   "gl_Position = vec4(position.x, position.y, position.z, 1.0);n"
                                   "}";

const GLchar* fragmentShaderSource = "#version 330 coren"
                                     "out vec4 color;n"
                                     "void main()n"
                                     "{n"
                                     "color = vec4(1.0f, 0.5f, 0.2f, 1.0f);n"
                                     "}n";

int main()
{
    glfwInit();

    glfwWindowHint( GLFW_CONTEXT_VERSION_MAJOR, 3 );
    glfwWindowHint( GLFW_CONTEXT_VERSION_MINOR, 3 );
    glfwWindowHint( GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE );
    glfwWindowHint( GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE );

    glfwWindowHint( GLFW_RESIZABLE, GL_FALSE );

    GLFWwindow* window = glfwCreateWindow( WIDTH, HEIGHT, "Learn OpenGL", nullptr, nullptr );

    int screenWidth, screenHeight;

    glfwGetFramebufferSize( window, &screenWidth, &screenHeight );

    if( nullptr == window )
    {
        std::cout << "Failed to create glfw window!n";
        glfwTerminate();

        return EXIT_FAILURE;
    }

    glfwMakeContextCurrent( window );

    glewExperimental = GL_TRUE;

    if( GLEW_OK != glewInit() )
    {
        std::cout << "Failed to initialize glew!" << std::endl;

        return EXIT_FAILURE;
    }

    glViewport( 0, 0, screenWidth, screenHeight );
    GLuint vertexShader = glCreateShader( GL_VERTEX_SHADER );
    glShaderSource( vertexShader, 1, &vertexShaderSource, NULL );

    glCompileShader( vertexShader );
    GLint success;
    GLchar infoLog( 512 );

    glGetShaderiv( vertexShader, GL_COMPILE_STATUS, &success );

    if( !success )
    {
        glGetShaderInfoLog( vertexShader, 512, NULL, infoLog );
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED" << infoLog << std::endl;
    }

    GLuint fragmentShader = glCreateShader( GL_FRAGMENT_SHADER );
    glShaderSource( fragmentShader, 1, &fragmentShaderSource, NULL );
    glCompileShader( fragmentShader );
    glGetShaderiv( fragmentShader, GL_COMPILE_STATUS, &success );

    if( !success )
    {
        glGetShaderInfoLog( fragmentShader, 512, NULL, infoLog );
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION::FAILEDn" << infoLog << std::endl;
    }

    GLuint shaderProgram = glCreateProgram();
    glAttachShader( shaderProgram, vertexShader );
    glAttachShader( shaderProgram, fragmentShader );
    glLinkProgram( shaderProgram );

    glGetProgramiv( shaderProgram, GL_LINK_STATUS, &success );

    if( !success )
    {
        glGetProgramInfoLog( shaderProgram, 512, NULL, infoLog );
        std::cout << "ERROR::SHADER::PROGRAM::LINKING::FAILEDn" << infoLog << std::endl;
    }

    glDeleteShader( vertexShader );
    glDeleteShader( fragmentShader );

    GLfloat vertices[] = { -0.5f, 0.5f, 0.0f, 0.5f, -0.5f, 0.0f, 0.0f, 0.5f, 0.0f };

    GLuint VBO, VAO;
    glGenVertexArrays( 1, &VAO );
    glGenBuffers( 1, &VBO );

    glBindVertexArray( VAO );
    glBindBuffer( GL_ARRAY_BUFFER, VBO );
    glBufferData( GL_ARRAY_BUFFER, sizeof( vertices ), vertices, GL_STATIC_DRAW );
    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof( GLfloat ), (GLvoid*)0 );
    glEnableVertexAttribArray( 0 );

    glBindBuffer( GL_ARRAY_BUFFER, 0 );
    glBindVertexArray( 0 );

    while( !glfwWindowShouldClose( window ) )
    {
        glfwPollEvents();
        glClearColor( 0.2f, 0.3f, 0.3f, 1.0f );
        glClear( GL_COLOR_BUFFER_BIT );

        glUseProgram( shaderProgram );
        glBindVertexArray( VAO );
        glDrawArrays( GL_TRIANGLES, 0, 3 );
        glBindVertexArray( 0 );

        glfwSwapBuffers( window );
    }

    glDeleteVertexArrays( 1, &VAO );
    glDeleteBuffers( 1, &VBO );

    glfwTerminate();

    return EXIT_SUCCESS;
}

…but when I execute a.out the window appears for a split second then disappears again.

How can I make it stay there?

I am compiling on bodhi linux 5.15.0-78-generic
with g++ -lGLEW -lGL -lglfw