Problem creating a file in an SD card

Other Hardware Storage
1

I have an arduino mega conected to an SD card reader (catalex branded), that at least detect the card as it Displays the info of the card, but when i am trying to create a file, it does not create it, i am using the following code:

if (SD.exists("data.txt")) {
  Serial.println("data.txt exists.");
} else {
  Serial.println("data.txt doesn't exist.");
}
File root=SD.open("data.txt", FILE_WRITE); //open of the File for writting
if (SD.exists("data.txt")) {
  Serial.println("data.txt exists.");
} else {
  Serial.println("data.txt doesn't exist.");
}

i also tried with this code:

File root2 = SD.open("file.txt", O_RDWR | O_APPEND);
    if (!root2) {
       // It failed, so try and make a new file.
        root2 = SD.open("file.txt", O_RDWR | O_CREAT);
        if (!root2) {
          // It failed too, so give up.
        Serial.println("Failed to open file.txt");
         }
    }
2

You need to format the card first.

3

Not only that, you need to do it in the proper manner. There is a sticky to that effect at the top of this forum.