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This example is for Wiring version 1.0 build 0100+. If you have a previous version, use the examples included with your software. If you see any errors or have comments, please let us know.

String substring() by Tom Igoe
Examples of how to use substring in a String

    void setup()
    {
      Serial.begin(9600);
      Serial.println("\n\nString  substring():");
    }

    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);
    }