count the quantity of prime number before my number
1 view (last 30 days)
Show older comments
Hi, I want to write a code to determine the quantity of prime number before the number selected by the user.
and I want to determine which numbers are prime inside of the loop. can you please help me?
x=input('Input a positive integer, or 0 to quit: ');
a=mod(x,1);
k=x-1;
for c=2:1:k
count=0;
for b=1:1:c
if mod(c,b)==0
count= count+1;
end
end
p=0;
if count==2
p=p+1; % c is prime
end
end
fprintf('count of prime numbers up to %g is: %g ',x,p);
end
0 Comments
Answers (1)
Andrei Bobrov
on 20 Mar 2019
x=input('Input a positive integer, or 0 to quit: ');
z = [2,3:2:x];
y= mod(z(:),z(:)');
out = z(all(tril(y) + triu(ones(size(y))),2));
0 Comments
See Also
Categories
Find more on Matrix Indexing in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!