/* String charAt() and setCharAt() Examples of how to get and set characters of a String created 27 July 2010 modified 2 Apr 2012 by Tom Igoe http://arduino.cc/en/Tutorial/StringCharacters This example code is in the public domain. */ 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.println("\n\nString charAt() and setCharAt():"); } void loop() { // make a string to report a sensor reading: String reportString = "SensorReading: 456"; Serial.println(reportString); // the reading's most significant digit is at position 15 in the reportString: char mostSignificantDigit = reportString.charAt(15); String message = "Most significant digit of the sensor reading is: "; Serial.println(message + mostSignificantDigit); // add blank space: Serial.println(); // you can alo set the character of a string. Change the : to a = character reportString.setCharAt(13, '='); Serial.println(reportString); // do nothing while true: while(true); }