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import java.util.Scanner;

public class TextMsgDecoder {
   public static void main(String[] args) {

      String message;
      Scanner keyboard = new Scanner(System.in);

      System.out.println("Enter text:");
      message = keyboard.nextLine();

      System.out.println("You entered: " + message);


     if (message.indexOf("IDK") > 0) {
        System.out.println("IDK: I don't know");
      }
      if (message.indexOf("BFF") > 0) {
        System.out.println("BFF: best friend forever");
      }
     if (message.indexOf("JK") > 0) {
        System.out.println("JK: just kidding");
      }
     if (message.indexOf("TMI") > 0) {
        System.out.println("TMI: too much information");
      }
     if (message.indexOf("TTYL") > 0) {
        System.out.println("TTYL: talk to you later");
      }
   }

}
Dave Newton
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Zamina Abdullahi
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    What input are you giving it? And have you tried `>=` instead of `>`? (The former will match at the start of the input line; the latter will match from the second character) – Andy Turner Oct 24 '18 at 23:01

2 Answers2

6
if (message.indexOf("IDK") > 0) {
  System.out.println("IDK: I don't know");
}

This will only detect IDK in a string which doesn't start with IDK, e.g. _IDK will be detected (since "_IDK".indexOf("IDK") == 1), but not IDK_ (since "IDK_".indexOf("IDK") == 0).

If you want to detect IDK anywhere including the start of the string, use either:

if (message.indexOf("IDK") >= 0) {

or, more idiomatically:

if (message.contains("IDK")) {
Andy Turner
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0

youcomparing the input string, where your typing "IDK" to the INDEXVALUE of IDK. its turning your string into an int. so there is no match

try this instead:

 if (Objects.equals(message, "IDK")) {
        System.out.println("IDK: I don't know");
      }

what your doing is getting the index of "IDK" which may be zero, but it wont be greater than 0, so your if never fires

Technivorous
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    Never compare strings with `==` ([How do I compare Strings in Java](https://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java?s=1|589.2131)) – Kevin Anderson Oct 25 '18 at 00:19
  • Syntax Error... not a typo. i caught this question in triage, and missed the java tag. its fixed now. – Technivorous Oct 25 '18 at 00:20