Why can't the program pass these assertions?

Question

My code: (class name is math and it implements an interface)

public boolean isPrime(int n){ for (int i=2; i<n; i++){ if (n%i==0){ return false; } } return true; }

Assertions needed to pass:

assert math.isPrime(2); assert math.isPrime(3); assert math.isPrime(53); assert !math.isPrime(55); assert !math.isPrime(24); assert !math.isPrime(-37337);

Oddly enough I've found that the method will pass the -37337 assertion by changing my code to:

for (int i=2; i<n; i++){ if (!(n%i==0)){ return true; } } return false;

But I can't seem to figure out how to pass all of the assertions

Note copied from wikipedia: "A prime number (or a prime) is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers...." - code is not testing for greater than 1! — user85421
– user85421, Commented Mar 9, 2020 at 19:00

Michael Bianconi · Accepted Answer · 2020-03-09 18:51:57Z

3

Because it never enters the loop (2 is greater than -37337)

answered Mar 9, 2020 at 18:51

Michael Bianconi

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