How do i fix the output of my code?

Doing some toy problems to get used to Matlab for university.

The following is the program:

a=rand(2,2);
c=1;
cmax=2;
r=1;
rmax=2;
while r<=rmax
    while c<=cmax
    a(c,r)=round(a(c,r),2);
    a(c,r)*100;
    c=c+1;
    end    
r=r+1;
c=1;
end
 
fprintf ('numero casuale: %i \n' ,a)

I expected the output to be something like:

numero casuale: 40

numero casuale: 80

numero casuale: 24

numero casuale: 12

But it turned out like:

numero casuale: 4.000000e-01

numero casuale: 8.000000e-02

numero casuale: 2.400000e-01

numero casuale: 1.200000e-01

Why did it divide the number by 10 and why did it add so many zeroes. How do i fix the outputs.

Answer 1

[Les Beckham]

a=rand(2,2)

a = 2×2

0.3808 0.2967 0.9243 0.0692

c=1;
cmax=2;
r=1;
rmax=2;
while r<=rmax
    while c<=cmax
    a(c,r)=round(a(c,r),2);
%     a(c,r)*100; << your original code isn't changing a here
    a(c,r)=a(c,r)*100;
    c=c+1;
    end    
    r=r+1;
    c=1;
end
format long g
a-round(a)

ans = 2×2

1.0e+00 * 0 0 0 8.88178419700125e-16

fprintf ('numero casuale: %i \n' , a);

numero casuale: 38 
numero casuale: 92 
numero casuale: 30 
numero casuale: 7.000000e+00 

fprintf ('numero casuale: %i \n' , round(a)); % round a again to handle floating point precision issues

numero casuale: 38 
numero casuale: 92 
numero casuale: 30 
numero casuale: 7 

[Gabriele Girasole]

what's the difference between %d and %i

[Les Beckham]

Actually, that wasn't the issue. The issue is that a is really of class double and isn't always able to be displayed properly with %i or %d (which are equivalent). For a while I thought that it was the issue. See updated answer.

[Gabriele Girasole]

thanks, rounding a again before printing, other than the error in line 8, was the issue. Thanks for the insight

[Les Beckham]

You are quite welcome.

Please Accept the answer if it solved your issue. Thanks.