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From: Mitchell, T. (HNA) <Tam...@hj...> - 2002-02-12 18:07:42
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Does any one have sample programs arrays and prime numbers?
I have a program Due Friday and am totally confused.
Can anyone point me in the right direction
Here is my exercise.
(The Sieve of Eratosthenes) A prime integer is any integer that is easily
divisible only by itself and 1. The Sieve of Eratosthenes is a method of
finding prime numbers. It operates as follows
a). Create an array with all elements initialized to 1 (true).
Array elements with prime subscripts will remain 1. All other array
elements will eventually be set to zero.
b). Starting with array subscript 2 (subscripts 1 must be prime),
every time an array element is found whose value is 1, loop through the
remainder of the array and set to zero every element whose subscript is
a multiple of the subscript for the element with value 1. For array
subscript 2, all elements beyond 2 in the array that are multiples of 2
will be set to zero(subscripts 4, 6, 8, 10, etc.) for array subscript 3, all
elements beyond 3 in the array that a are multiples of 3 will be set to zero
(subscripts 6, 9, 12, 15 etc) and so on.
When this process is complete, the array elements that are still set to one
indicate that the subscript is a prime number. These subscripts can then be
printed. Write a program that uses an array of 1000 elements to determine
and print the prime numbers between 1 and 999. Ignore element 0 of the
array.
This is what I have so far
#include<iostream>
using std::cout;
using std::endl;
#include<iomanip>
int main()
{
const int i[1000];
}
Not much.
Tamra Y. Mitchell
Heinz North America
Database & Operating Systems Analyst
(412) 237-5232 Work
(412) 996-9078 Cell Phone
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