Example of writing to a file

src/19Sdcard/02writing_file/02writing_file.ino

@@ -0,0 +1,49 @@
+#include <SPI.h>
+#include <SD.h>
+
+File myFile;
+
+// change this to match your SD shield or module;
+const int chipSelect = 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 Leonardo only
+  }
+
+
+  Serial.print("Initializing SD card...");
+
+  if (!SD.begin()) {
+    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("arduino.txt", FILE_WRITE);
+
+  // if the file opened okay, write to it:
+  if (myFile) {
+    Serial.println("Writing to arduino.txt...");
+    for(int i = 0; i < 10; i++){
+        myFile.print("Testing: ");
+        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 arduino.txt");
+  }
+}
+
+void loop()
+{
+  // nothing happens after setup
+}