| /* | |
| String length() | |
| Examples of how to use length() in a String. | |
| Open the Serial Monitor and start sending characters to see the results. | |
| created 1 Aug 2010 | |
| by Tom Igoe | |
| This example code is in the public domain. | |
| https://www.arduino.cc/en/Tutorial/BuiltInExamples/StringLengthTrim | |
| */ | |
| String txtMsg = ""; // a string for incoming text | |
| unsigned int lastStringLength = txtMsg.length(); // previous length of the String | |
| 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 length():"); | |
| Serial.println(); | |
| } | |
| void loop() { | |
| // add any incoming characters to the String: | |
| while (Serial.available() > 0) { | |
| char inChar = Serial.read(); | |
| txtMsg += inChar; | |
| } | |
| // print the message and a notice if it's changed: | |
| if (txtMsg.length() != lastStringLength) { | |
| Serial.println(txtMsg); | |
| Serial.println(txtMsg.length()); | |
| // if the String's longer than 140 characters, complain: | |
| if (txtMsg.length() < 140) { | |
| Serial.println("That's a perfectly acceptable text message"); | |
| } else { | |
| Serial.println("That's too long for a text message."); | |
| } | |
| // note the length for next time through the loop: | |
| lastStringLength = txtMsg.length(); | |
| } | |
| } | |