OPEN different Filename from SD-Card

Hello,

I am kinda new with Arduino, but I try for a project to open different filenames from a sd-card with some data in this .txt. When I unplug the sd-card and put new .txt files on it, I want to open the files behind each other with a delay.

I use a Arduino Uno with a SD-Card-Module.

As File Example:
File 1: text.txt
File 2: number.txt

I tried to put the filename in a string and then open it, but this doesnt work.

Code:

  File root = SD.open("/"); //open sd card
  File file = root.openNextFile(); //first/next file 
  char filename[]= file.name(); //file name to string (dont work, put in println it is working?)
  File currentfile = SD.open(filename); //variable to work with
  if (currentfile) {
    Serial.println("content:");

    // reading file
    while (currentfile.available()) {
      Serial.write(currentfile.read());
    }
    // open file
    Serial.println("\n");
    currentfile.close();
  } else {
    // if the file didn't open
    Serial.println("error opening file");
  }

in SD.open() must be the filename with "", I want there the current/next filename from the sd-card.

Greetings.

Wouldn't be more simple to just use instance named "file" directly? I mean, the file is already opened by root.openNextFile(), so why doing that again?