Chapter 4: Programming in Matlab - College of the Redwoods

Section 4.3 Functions in Matlab 357
n=7;
nterm=fib(n);
fprintf(’The n = %d term of the sequence is: %d\n’, n,nterm)
The output is correct.
The n = 7 term of the sequence is: 13
Readers should check the behavior for other values of n.
19. Save these lines as twinprimes.m. The || is Matlab’s “short-circuit or.” If
the first the first part of the “or” expression evaluates as true, then the interpreter
doesn’t bother with the second part of the “or” expression, as it is already true.
Note that we’ve also included an error message, which when executed, displays
to the command window and stops program execution.
function twins=twinprimes(a,b)
if round(a)~=a || round(b)~=b
error(’The inputs a and b must be integers.’)
end
candidates=a:b;
twins=[];
candidates=candidates(isprime(candidates));
len=length(candidates);
for k=1:(len-1)
if candidates(k+1)-candidates(k)==2
twins=[twins;candidates(k:k+1)];
end
end
Test the function.