File content as of revision 0:1a07e19d701d:

// Temperature logging demo - record temperatures to SD card and print them to
// the console every 10 seconds

#include "mbed.h"
#include "SDFileSystem.h"

// Analog input (pin 15)
AnalogIn ain(A2);

// USB serial (tx, rx)
Serial pc(USBTX, USBRX);

// SD card (SPI pins)
SDFileSystem sd(D11, D12, D13, D10, "sd");

// Timer for our timestamps
Timer timer;

int main() {

    FILE *file;
    float degrees_c;
    int i;
    int c;

    // Start our timer
    timer.start();

    // Open file for writing
    file = fopen("/sd/temp_data.txt", "w");
    if ( file == NULL ) {
        error("ERROR: Could not open file for writing!\n\r");
        return -1;
    }

    // Tell the user we need to wait while we collect some data
    pc.printf("\nCollecting data (Do not remove SD Card!) ...\n\r");

    // Collect temperatures with timestamps every second
    for(i = 0; i < 10; i++) {
        
         float  Temp = ain.read_u16(); // Read analog value 
         float voltage_in = (float) 3300 / 65535 * (float) Temp;
        degrees_c = (voltage_in / 10);
        fprintf(file, "%2.2fs: %3.1f deg C\n\r", timer.read(), degrees_c);
        wait(1);
    }

    // Close file and re-open it for reading
    fclose(file);
    file = fopen("/sd/temp_data.txt", "r");
    if ( file == NULL ) {
        error("ERROR: Could not open file for reading!\n\r");
        return -1;
    }

    // Print results to console
    pc.printf("Temperature data:\n\r");
    while(1) {
       c = fgetc(file);
       if ( c == EOF ) {
           break;
       }
       pc.putc(c);
    }

    // Close the file and finish
    fclose(file);
    pc.printf("Done! Safe to remove SD card\n\r");

    return 0;
}