Problem on printing value of plot

I'm trying to get input for sine wave and then plot it while printing values in command windows. But i'm getting more values than i expected to get.

Is there anything wrong in this code?

clc;

clear;

N = input('Length=') ;

fs = input('Sampling Frequency=') ;

f1 = input('Frequency=') ;

ts = 1/fs ;

t = -(N/(2*fs)):ts:(N/(2*fs)) ;

y = sin(2*pi*f1*t) ;

plot(t,y);

fprintf('Time=%4.1f Amp=%6.1f \n' , t , y) ;

Answer 1

[KL]

You're creating vectors and so when you use them (t,y) in fprintf, you get multiple values.

[Gombo Khorloo]

I mean in this case fprintf must print values of t between -(N/2*fs) to (N/2*fs) but it is printing more values after this as you can on the screenshot.Thanks for the fast reply.

[KL]

change the last line to something like

fprintf('Time=%4.4f Amp=%6.4f \n' , t , y) ;

%4.4f means 4 digits after the decimal place.

[Gombo Khorloo]

No,no i mean let's think N=1024,fs=200,f1=1.So in this case fprintf must print value of t from -2,6 upto +2,6 but as i can see from command window fprintf starts printing unexpected values after +2,6.This is problem that i'm looking for answer.I don't understand this.Sorry for taking your time.

[Steven Lord]

The fprintf function is vectorized, but perhaps not in the way you think. When you have multiple format operators in the format specification and you pass multiple data inputs into fprintf, it does not take the first elements of each of the data inputs to fill in the format operators for the first line printed, the second elements of each for the second line, etc. It iterates through the columns of the first data input, then moves to the columns of the second data input, etc.

x = 1:5;
y = 11:15;
fprintf('%d %d\n', x, y)

You might expect this to display:

 1 11
 2 12
 3 13
 4 14
 5 15

Instead it displays:

 1 2
 3 4
 5 11
 12 13
 14 15

To get what you expected, stack x and y on top of one another as per the Write Tabular Data to Text File example on the documentation page for fprintf.

fprintf('%d %d\n', [x; y])

[Gombo Khorloo]

Thank you very much.Helped so much :)