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/*
  String substring()

  Examples of how to use substring in a String

  created 27 Jul 2010,
  modified 2 Apr 2012
  by Zach Eveland

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/StringSubstring
*/
 

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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();
}
 

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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);
}