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Java Java Arrays Iteration Enhanced For Loop

Posted by Evan Hayes
Evan Hayes
4,093 Points

System.out.printf or System.out.println

I have done a couple of videos and notice that they use the printf method a lot but the println works the same way is it a problem that i use the println method because it looks a lot more readable to me.

for example in the video he uses System.out.printf("Hey %s the movie starts at 7", friend);

but the System.out.println("hey" + friend + "the movie starts at 7");

gives you the same results is there a reason to use one over the other?

2 Answers

Juraj Sallai
Juraj Sallai
7,188 Points
Juraj Sallai
Juraj Sallai
7,188 Points

Hi Evan,

Method println() prints String on new line. You can concatenate multiple items with +. Method printf() prints formatted output in the way you mentioned: 

System.out.printf("Hey %s the movie starts at 7", friend);

Which looks better than something like this, especially for big output Strings.

System.out.println("hey" + friend + "the movie starts at 7");

So it is good to avoid confusion when you are printing big Strings. Pretty good explanation is also here:

https://teamtreehouse.com/community/difference-between-systemoutprintf-and-systemoutprintln

Daniel Phillips
Daniel Phillips
26,940 Points
Daniel Phillips
Daniel Phillips
26,940 Points

printf gives you a little more flexibility when you want to print something multiple times.

e.g. "Hey Craig, the movie starts at 7, Craig. See you then Craig."

With println, you would do it like this:

String friendToInviteToMovies = "Craig";
System.out.println("Hey " + friendToInviteToMovies + ", the movie starts at 7, " + friendToInviteToMovies + ". See you then " + friendToInviteToMovies + ".";

But with printf (or the new format), you can do this:

String friendToInviteToMovies = "Craig";
System.out.printf("Hey %1$s, the movie starts at 7, %1$s. See you then %1$s.%n", friendToInviteToMovies);