#include <SD.h>

#define CS_PIN 10

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(CS_PIN)) {
    Serial.println("initialization failed!");
    while (1);
  }
  Serial.println("initialization done.");
}

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

  // if the file opened okay, write to it:
  if (myFile) {
    //Serial.print("Writing to test.txt...");
    myFile.println("testing 1, 2, 3.");
    // close the file:
    myFile.close();
    //Serial.println("done.");
  } else {
    // if the file didn't open, print an error:
    Serial.println("error opening wokwi.txt");
  }

  delay( 1000 );
  // re-open the file for reading:
  myFile = SD.open("wokwi.txt", FILE_READ);
  if (myFile) {
    Serial.println("Read wokwi.txt:");

    // read from the file until there's nothing else in it:
    while (myFile.available()) {
      Serial.write(myFile.read());
    }
    // close the file:
    myFile.close();
  } else {
    // if the file didn't open, print an error:
    Serial.println("error opening wokwi.txt");
  }
}