error in initialising vao (glCreateVertexArrays()) - opengl

Question

In order to understand how to use two buffers and binding it to vao i am trying to display a triangle with some color. I am getting an error like this
First-chance exception at 0x00000000 in ConsoleApplication12.exe: 0xC0000005: Access violation executing location 0x00000000.
When i try to debug, this error is caused by the line in the code
glCreateVertexArrays(1, &vao);
I did initialized vao, but i do not understand why the error occurred. Please help me..
Here is the code
#include <stdlib.h>
#include<iostream>
#include <GL/glew.h>
#include <GL/freeglut.h>
#include "glm/glm.hpp"
#define BUFFER_OFFSET(offset) ((GLvoid *) offset)
GLuint program;
static int timeFor =0;
GLuint vPos;
GLuint buffer[2];
GLuint vao = 0;
void init()
{
static const GLfloat positions[] = { 0.1f, 0.2f, 0.3f, 0.0f};
static const GLfloat colors[] = { 1.0f, 0.0f, 0.0f, 1.0f};
glCreateVertexArrays(1, &vao);
glCreateBuffers(2, &buffer[0]);
glNamedBufferStorage(buffer[0], sizeof(positions), positions, 0);
glVertexArrayVertexBuffer(vao, 0, buffer[0], 0, sizeof(glm::vec4));
glVertexArrayAttribFormat(vao, 0, 4, GL_FLOAT, GL_FALSE, 0);
glVertexArrayAttribBinding(vao, 0, 0);
glNamedBufferStorage(buffer[1], sizeof(colors), colors, 0);
glVertexArrayVertexBuffer(vao, 1, buffer[1], 0, sizeof(glm::vec4));
glVertexArrayAttribFormat(vao, 1, 4, GL_FLOAT, GL_FALSE, 0);
glVertexArrayAttribBinding(vao, 1, 1);
const char* vSource = {
"#version 330\n"
"layout (location = 0) in vec4 offset;"
"layout (location = 1) in vec4 color;"
"out vec4 fColor;"
"void main() {"
"const vec4 vertices[3] = vec4[3](vec4( 0.25, -0.25, 0.5, 1.0), vec4( -0.25, -0.25, 0.5, 1.0), vec4( 0.25, 0.25, 0.5, 1.0));"
"gl_Position = vertices[gl_VertexID] + offset;"
"fColor = color;"
"}"
};
const char* fSource = {
"#version 330\n"
"in vec4 fColor;"
"out vec4 fragColor;"
"void main() {"
"fragColor = fColor;"
"}"
};
GLuint vShader, fShader;
vShader = glCreateShader(GL_VERTEX_SHADER);
fShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(vShader, 1, &vSource, NULL);
glShaderSource(fShader, 1, &fSource, NULL);
glCompileShader(vShader);
glCompileShader(fShader);
program = glCreateProgram();
glAttachShader(program, vShader);
glAttachShader(program, fShader);
glLinkProgram(program);
glClearColor(1.0f, 1.0f, 0.0f, 1.0f);
}
void reshape(int width, int height)
{
glViewport(0, 0, width, height);
}
void display()
{
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(program);
glDrawArrays(GL_TRIANGLES, 0, 3);
glutSwapBuffers();
}
void main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
glutCreateWindow(argv[0]);
glewInit();
init();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutMainLoop();
}

Answer 1

I checked my openGL version its 4.4, in which glCreateVertexArrays is not supported instead of that glGenVertexArrays must be used.