My function is running fine for small no but not for big no.Can anybody explain?
1 view (last 30 days)
Show older comments
function k=next_prime(n)
k=2;
while(k>2)
if(isprime(k)==1)
if(k>n)
return
else
k=k+1;
end
else
k=k+1;
end
end
1 Comment
Walter Roberson
on 25 Sep 2021
k=2;
while(k>2)
You initialize k to 2, but you check k>2 which is immediately false.
Accepted Answer
DGM
on 25 Sep 2021
Edited: DGM
on 25 Sep 2021
Consider:
a = next_prime(17560)
b = next_prime(5346551)
function k = next_prime(n)
k = n;
while true
if isprime(k)
break;
end
k=k+1;
end
end
3 Comments
Walter Roberson
on 25 Sep 2021
Edited: Walter Roberson
on 25 Sep 2021
What is an example of an input that it gives the wrong answer for?
Your code is slow. There is no point in testing any number that is lower than the input, n, because it does not matter if any of them are prime: all that matters is starting from n . And making sure that you carefully define what is intended to happen if the input is already a prime.
More Answers (0)
See Also
Categories
Find more on Loops and Conditional Statements 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!