how can I download my file residing in local repository

I am new to CodeIgniter and was working on downloading a file. However, I want to download a file that resides on my local machine, I am able to locate the file by providing the path, also the file gets downloaded with a File type, However, I want my file to be in .csv format

Here goes my Controller’s download function:

public function download()
{   
        $state_id=$this->input->post('state'); // gets me the state-id from viw's dropdown
        $this->load->helper('download'); // Load download helper
        $file="C:\Usersusernew\Desktop\New folder\".$state_id.".csv";
        $filename=$state_id.'.csv';
        
    
        if (file_exists($file))
        {
                $data = file_get_contents($file);       //check file exists 
                force_download($fileName,$data);
            }
            else{
                echo"not working!";
            }    
        }   

Where am I going wrong?

Answer

The force_download() takes in two parameters, i.e. the file name and the data to be written to that file. As the file already consists of some sample data, therefore, the function goes like this:

 public function download()
{   
        $state_id=$this->input->post('state'); // gets me the state-id from viw's dropdown
        $this->load->helper('download'); // Load download helper
        $filename=$state_id.'.csv';
        $file="C:\Usersusernew\Desktop\New folder\".$filename;
        
        
    
        if (file_exists($file))                    //check file exists
        {
                force_download($file,NULL);      //NULL as the file already has data
            }
            else{
                echo"not working!";
            }    
        }