What is the pseudocode that outputs all prime numbers between 2 and 100?

Answer 1

function is_prime (n) such that n>=0

if n<2 return false // 0 and 1 are non-prime

if n%2=0 return n=2 // 2 is the only even prime

max_div = sqrt (n) + 1

for div=3 to max_div step 2 // odd factors (3, 5, 7, 9, etc)

if n%div==0 then return false // div is a factor of n, thus n is non-prime

next div

return true // if we get this far, n has no factors, thus n is prime

function main // test the algorithm

for n=2 to 100 step 1 // inclusive if is_prime (n) = true then output n next n

Note: % is the modulo operator, returning the remainder after division. E.g., n%d returns 0 when d is a factor of n, and non-zero if d is not a factor of n

Answer 2

function prime (input: number) output: true if number is prime, otherwise false

{

// Test even values.

if number modulo 2 true

{

print number

}

number = number + 1

}

}

function main (input: none) output: none

{

print primes (2, 100)

}