C Library Functions - i_is_prime (3)
NAME
i_is_prime(3f) - [M_factor] Determine if a number is prime using Sieve of Erasthosthenes (LICENSE:UNKNOWN)
CONTENTS
Synopsis
Description
Version
Author
Parameters
Returns
Examples
SYNOPSIS
function i_is_prime(n)
integer,intent(in) :: n
DESCRIPTION
A simple, unoptimized sieve of Erasthosthenes is used to check whether N can be divided by any integer between 2 and SQRT(N).
VERSION
29 November 1998
AUTHOR
John Burkardt
PARAMETERS
n Input, integer N, the integer to be tested.
RETURNS
Output logical I_IS_PRIME(3f) is TRUE if N is prime, and FALSE otherwise. Note that negative numbers and 0 are not considered prime.
EXAMPLES
sample program
program demo_i_is_prime use M_factor, only: i_is_prime implicit none integer :: i integer :: icount=0 integer :: isum=0 integer,parameter :: n= 10000 do i=2, n if(i_is_prime(i))then icount=icount+1 isum=isum+i write(*,*)icount,i endif enddo write(*,*)’number of primes between 2 and ’,n,’ is ’,icount write(*,*)’sum of primes between 2 and ’,n,’ is ’,isum write(*,*)i_is_prime([4,6,8,9,10,12,14,15,16,18]) write(*,*)all(.not.i_is_prime([4,6,8,9,10,12,14,15,16,18])) write(*,*)any(.not.i_is_prime([4,6,8,9,10,12,14,15,16,18])) end program demo_i_is_prime
| Nemo Release 3.1 | i_is_prime (3) | February 23, 2025 |
