arduino sd card module

#include <SPI.h>#include <SD.h>File myFile;void setup() {// Open serial communications and wait for port to open:Serial.begin(9600);while (!Serial) {; // wait for serial port to connect. Needed for native USB port only}Serial.print("Initializing SD card...");if (!SD.begin(10)) {Serial.println("initialization failed!");while (1);}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("test.txt", FILE_WRITE);// if the file opened okay, write to it:if (myFile) {Serial.print("Writing to test.txt...");myFile.println("This is a test file :)");myFile.println("testing 1, 2, 3.");for (int i = 0; i < 20; i++) {myFile.println(i);}// close the file:myFile.close();Serial.println("done.");} else {// if the file didn't open, print an error:Serial.println("error opening test.txt");}}void loop() {// nothing happens after setup}