/* String substring() Examples of how to use substring in a String created 27 July 2010, modified 2 Apr 2012 by Zach Eveland http://www.arduino.cc/en/Tutorial/StringSubstring 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 native USB port only } // send an intro: Serial.println("\n\nString substring():"); Serial.println(); } void loop() { // Set up a String: String stringOne = "Content-Type: text/html"; Serial.println(stringOne); // substring(index) looks for the substring from the index position to the end: if (stringOne.substring(19) == "html") { Serial.println("It's an html file"); } // you can also look for a substring in the middle of a string: if (stringOne.substring(14, 18) == "text") { Serial.println("It's a text-based file"); } // do nothing while true: while (true); }