Using fprintf() and disp() functions to display messages to command window in MATLAB? - matlab

Question

Currently working on a project in which I must take multiple user-inputs. Because my input prompts must outline specific formatting to the user regarding how they should input their values, this makes each input prompt rather lengthy and so I've deemed it appropriate to separate each one with a line break so that it's easy to tell them apart/so that it looks nice. The last prompt is two lines long, so it would be hard to distinguish this one from the rest if they were all jumbled together rather than separated by line breaks.
I've explored the usage of fprintf() and disp(), and have found that fprintf() has some tricky behavior and sometimes will not work without including things like fflushf(), etc. Moreover, I've read that fprintf() is actually purposed for writing data to text files (from the MathWorks page, at least), and using it for another purpose is something I could definitely see my professor deducting points for if there is indeed an easier way (we are graded very harshly on script efficiency).
The disp() command seems to be more in-line with what I'm looking for, however I can't find anything on it being able to support formatting operators like \n. For now, I've resorted to replacing the usage of \n with disp(' '), however this is certainly going to result in a deduction of points.
TL;DR Is there a more efficient way to create line-breaks without using fprintf('text\n')? I'll attach a portion of my script for you to look at:
disp('i) For the following, assume Cart 1 is on the left and Cart 3 is on the right.');
disp('ii) Assume positive velocities move to the right, while negative velocities move to the left.');
prompt = '\nEnter an array of three cart masses (kg) in the form ''[M1 M2 M3]'': ';
m = input(prompt);
prompt = '\nEnter an array of three initial cart velocities (m/s) in the form ''[V1 V2 V3]'': ';
v0 = input(prompt);
disp(' ');
disp('Because the initial position of the three carts is not specified,');
prompt = 'please provide which two carts will collide first in the form ''[CartA CartB]'': ';
col_0 = input(prompt);

Answer 1

You can get disp to display a new line with the newline function. Putting multiple strings in square bracket will concatenate them.
disp(['Line 1' newline 'Line 2'])
You mention using fprintf, but as you found this is meant for writing to files. You can use the sprintf function to display the same formatted strings if desired.
disp(sprintf('Line 1 \nLine 2'))

Answer 2

In addition to Matt's solution, I figured out another way to solve my problem and wanted to post it here for anyone in the future with the same problem.
After some experimentation and some thought, I figured the most efficient way to do this (ideally) would not involve using disp() or fprintf() at all and instead would, in theory, involve actually manipulating the input prompts themselves to appear on multiple lines (rather than adding 'dummy' lines before the last line of each prompt, to make it seem as if it was all part of the prompt itself). I've been aware this whole time that simply a newline character \n will give me a linebreak in the middle of the sentence, and in theory this would work. But because the very last prompt is two lines long, simply typing one line with \n halfway through would make that line of code very long, which is what I was trying to avoid in the first place.
I realize my initial question didn't explicitly mention concatenating two (or more) strings to form an input prompt that appears on multiple lines both in the console and in the script itself, but that's essentially where I was going with this post and I apologize for any lack of clarity regarding this.
Anyways, I fixed this problem without having to use disp() or fprint() by declaring the prompt as a string array, rather than as a single string with the preceding lines of the prompt specified above it using disp() and/or fprintf() as you can see in the code I originally provided in the question. Here's how it looked before:
disp(' ');
disp('Because the initial position of the three carts is not specified,');
prompt = 'please provide which two carts will collide first in the form ''[CartA CartB]'': ';
col_0 = input(prompt);
versus how it looks now:
prompt = ['\nBecause the initial position of the three carts is not specified, please',...
'\nprovide which two carts will collide first in the form ''[CartA CartB]'': '];
col_0 = input(prompt);
In short, you can concatenate portions of the entire prompt by declaring it as a string array and inserting \n where you see fit.