How to read txt file IN LINE from SD card?

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C++

C

Arduino

Hi, I try to read file from SD card using arduino + ethernet shiled.
I have login.txt with content:
41001662
41001536
41001324
.....
I can read all file, but I want to read line by line of login.txt
How can I read 41001662 to data1, 41001365 to data2? read line by line?
Here is my code. How can I fix it?
///////////////////

#include <SD.h>
File myFile;
void setup()
{
  Serial.begin(9600);
  Serial.print("Initializing SD card...");
  pinMode(10,OUTPUT);

  if(!SD.begin(4))
  {
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");
  myFile = SD.open("login.txt");
  if(myFile)
  {
    Serial.println("login.txt: ");
    while(myFile.available())
    {
      Serial.write(myFile.read());
    }
    myFile.close();
  }
  else
  {
    Serial.println("error opening test.txt");
  }
}
void loop()
{

}