Serial Println Vs Print

[Mireille Duhon]

printprint() method in Java is used to display a text on the console. This text is passed as the parameter to this method in the form of String. This method prints the text on the console and the cursor remains at the end of the text at the console. The next printing takes place from just here. Various print() methods:

println(): println() method in Java is also used to display a text on the console. This text is passed as the parameter to this method in the form of String. This method prints the text on the console and the cursor remains at the start of the next line at the console. The next printing takes place from next line. Various println() methods:

The println() function writes to the console area, the black rectangle at the bottom of the Processing environment. This function is often helpful for looking at the data a program is producing. Each call to this function creates a new line of output. More than one parameter can be passed into the function by separating them with commas. Alternatively, individual elements can be separated with quotes ("") and joined with the addition operator (+).

Before Processing 2.1, println() was used to write array data to the console. Now, use printArray() to write array data to the console.

Note that the console is relatively slow. It works well for occasional messages, but does not support high-speed, real-time output (such as at 60 frames per second). It should also be noted, that a println() within a for loop can sometimes lock up the program, and cause the sketch to freeze.

Prints data to the serial port as human-readable ASCII text followed by a carriage return character (ASCII 13, or '\r') and a newline character (ASCII 10, or '\n'). This command takes the same forms as Serial.print().

Serial: serial port object. See the list of available serial ports for each board on the Serial main page.

val: the value to print. Allowed data types: any data type.

format: specifies the number base (for integral data types) or number of decimal places (for floating point types).

Probably the final syntax choice is because other languages, like java and C have also println. I would also have chosen to keep print for the most common (I think) case that println is, but others might prefer otherwise.

yes your are right. I personally like print because sound more natural to write and talk as Python background.

I personally think the way of writing of python (more natural) and more easier learning curve, that part should be import to julia (yes i got to know, julia have even more cool features) but anyway, but i feel fear if borrowed from c or java (steeper learning curve) syntaxes.

As a non-former-python regular user I find the Julia syntax much easier (with the only exception of that and the and vs. &&). Otherwise, the syntax for functions, structures, math in general, loop ranges, an many other, is cleaner in Julia. But we always find that what we are used to is simpler. That is normal.

The line will be printed with a linefeed, so the number will be entered on the line underneath it.

As in my C++ code, I want the number to show in the terminal next to the statement.

But when I use print!, the statement isn't displayed and the cursor goes to a blank 2nd line to wait for input.

I think that @DanielKeep has invented a very rusty way of doing input with scan-rules, something the standard library simply doesn't include by itself. What do you think @jzakiya, is scan-rules understandable for a newcomer to Rust?

Don't you think that this kind of interactive input is a task that's predominantly common when learning programming, in particular in older books? I doesn't have that much connection to real world tasks.. maybe that's a boring perspective, but I think it's part of the reason why it's not prioritized in Rust.

The current Gold Standard system languages are C/C++ (Linux kernel, GIT, etc). For marketing, political, and social, et al reasons, the more you can do to provide out-of-the-box comparable functionality the better you will be at attracting the widest possible audience.

The reason Rust's standard library doesn't have very expressive support for writing interactive UNIX command line programs is that Rust is a very young language with a very small standard library. As things evolve, other crates will be developed which will provide expressive APIs for interacting with the command line. Possibly some day one of these solutions will be integrated into the standard library.

Some languages, including C++ and Perl, automatically flush standard output on reads from standard input when a terminal is detected. This helps with simple examples like the one you posted, but leads to more confusing failures later in the learning curve; it might be good for a pre-RFC (I have no opinion on whether Rust should do this at this time).

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I have been learning java with treehouse for the past few days and I'm confused about the difference between "printf" and "println". Furthermore, I also don't know what does the term "console" mean and what it is for? sometimes people use "console.printf" and "System.out.printf". What are they?

First for the difference in println and printf. The names are short versions of their function. println is short for "print line", meaning after the argument is printed then goes to the next line. printf is short for print formatter, it gives you the ability to mark where in the String variables will go and pass in those variables with it. This saves from having to do a long String concatenation. Here are a few examples, I will be putting '_' where the computer is left and where it would put stuff if sent another print statement.

The word console is used in code basically as a wrapper for System.out. Some TreeHouse challenges have code that is abstracted away from you. This includes the declaration of a console variable. IIRC the declaration will have System.out in it.

System.out is the raw output stream Object for the JVM. You can think of this stream as a conveyer belt of text to the user. At the user end of the conveyer belt it displays the text to whatever console is associated with the JVM (i.e. Windows cmd, Mac terminal, IDE console etc).

The Console Object in code is like a String processing machine at our end of the input/output stream conveyer belts. It gives us more advanced options when doing input/output, as well as combining both streams into one Object.

A good illustration for this would be on the input side. With the Console Object we get a readPassword() method. This will get a String from the user while not displaying the characters the user is typing. If we tried getting the password directly from the input stream System.in we would have no way of hiding what the user is typing.

Unfortunately I can't come up with a good illustration of the benefit of Console for the output stream, cause they are both just putting text on a screen. In the coding real world it will be better to use Console (or similar Object) if you will be doing much user input/output. I really only use System.out for quick one time outputs that don't need any fancy-ness with it, such as debugging.

Can console be used the same way as System.out.print ? I am taking a java class in college now and the teacher only has knowledge on System.out.print. If I were to replace all my System.out.print with console.print will my code still work?

Ok, Tx JCA,

I think this is what I need.

I'm not an experienced Arduino user. Correct me if I'm wrong, but I have to download that library and put it in the Arduino folder? Then I have to put in a certain name in the program (#name) so I can use the

Hello Ray,

I have not knowingly enabled it. When I wrote the tutorial I didn't know sprintf wasn't supposed to work. Maybe for the benefit of anyone reading this it would help to explain how to enable it if needed.

...and redo that every time you update to a new version. And now the beginners that want to use your sketch must go through this complex process. All for what? This is antithetical to everything Arduino stands for.

I have always assumed that the core of both functions is the same with the only difference being that printf sends the output to the serial port and sprintf to a file. From this assumption comes the further assumption that if one is available then the other must be too. Is this wrong?

PerryBebbington:

Hello Ray,

I have not knowingly enabled it. When I wrote the tutorial I didn't know sprintf wasn't supposed to work. Maybe for the benefit of anyone reading this it would help to explain how to enable it if needed.

PerryBebbington:

I have always assumed that the core of both functions is the same with the only difference being that printf sends the output to the serial port and sprintf to a file. From this assumption comes the further assumption that if one is available then the other must be too. Is this wrong?

Even though the underlying capability for both is provided by the compiler toolchain, the Print class is part of the Arduino core library, so if the core library author doesn't add that function to the class then it won't be available.

Arduino has intentionally not done this because they feel that it leads to less beginner friendly code. There have been several discussions about this, but you can find one at this link and the mailing list link off that thread:

printf() is present by default. It's just not connected to anything.

Connecting it isn't that hard, but is also cpu-dependent in annoying ways

printf() does use the same core code as sprintf()

AVR printf is rather nicely optimized, but ARM printf() is depressingly large (sucks in filesystem code, for example. Because sprintf() is handled by using a special "file" that means a string. Sigh.) OTOH, most ARM chips have large flash memory, so it maybe it doesn't matter.

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