basic SD card read/write

/*
  SD card read/write

 This example shows how to read and write data to and from an SD card file
 The circuit:
 * SD card attached to SPI bus as follows:
 ** MOSI - pin 11
 ** MISO - pin 12
 ** CLK - pin 13
 ** CS - pin 10

 created   Nov 2010
 by David A. Mellis
 modified 9 Apr 2012
 by Tom Igoe

 This example code is in the public domain.

 */

#include <SD.h>

File myFile;

char character;
char last_char;
int line_num = 1;

void setup()
{
 // Open serial communications and wait for port to open:
  Serial.begin(9600);
   while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }


  Serial.print("Initializing SD card...");
  // On the Ethernet Shield, CS is pin 4. It's set as an output by default.
  // Note that even if it's not used as the CS pin, the hardware SS pin
  // (10 on most Arduino boards, 53 on the Mega) must be left as an output
  // or the SD library functions will not work.
   pinMode(10, OUTPUT);

  if (!SD.begin(10)) {
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");

  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  myFile = SD.open("teamlist.txt");

  if (myFile) {
    Serial.println("teamlist.txt:");

    // read from the file until there's nothing else in it:
    while (myFile.available()) {
      character = myFile.read();
      if (last_char == '\n')
      {
        line_num = line_num + 1;
      }
      if (line_num == 2)
      {
      Serial.write(character);
      }
      last_char = character;
    }

    int num_byte = myFile.size();
    Serial.println("File size:");
    Serial.println(num_byte);
    // close the file:
    myFile.close();
    Serial.println("File closed");
  } else {
    // if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  }
}

void loop()
{
    // nothing happens after setup
}