Get a C + + implementation of optimization filtering method for prime numbers less than n

Correlation theorem and inference of twin primes (adjacent primes with 2 interval) P1: When n is not less than 6 and N-1 and n+1 are twin primes, then n must be a multiple of 6 T1: When n is not less than 1 and n=6x-1 or n=6x+1 is not a prime number, then n must not be 2 and 3 times Number P2: When n is not less than 5 o'clock, if n is prime, then n mod 6 = 1 or n mod 6 = 5T2: A number greater than 5 has and only divisible by 6 is 1 or 5 is possible prime number

The remainder of a number divisible by 6 may be 1,2,3,4,5 but the remainder of 2,3,4 is definitely composite

The specific code is as follows

/* *************************************************************** * NAME:select_prime.cpp * DESC: * author:l IU Dongguo ([email protected]) * version:1.0 * create:2015-04-09 13:59:45 * lutime:2015-04-10 01:53:40 * * Copyright ( c) 2007-2015 Abodu.com,inc. All Rights Reserved * *************************************************************** * *#include <stdio.h>#include <math.h>#include <string.h>Char* GETPRIMESLESSN (intNSize)//nsize is the upper value{intFlen= nSize;Char* flag=New Char[Flen];//    memset(Flag,' y ', Flen); flag[0]=flag[1]=' s ';//Exclude 0 and 1     for(intI=2;i*i<nsize;) { for(intJ=i*i;j<nsize;j+=i) {flag[j]=' n '; }//Probe The possible steps of the next prime number from the current prime        if(i==2)//2 Special: The distance to 3 is 1.{i++;Continue; }one of the//2,4,6i+=2;if(flag[i]==' n ')//2 was marked.{i+=2;if(flag[i]==' n ')//4 was marked before.i+=2; }    }returnFlag;}intMainintargcChar*argv[]) {intflen=10000;Char* FLS=GETPRIMESLESSN (Flen);intI=0, cnt=0; while(I<=flen) {if(fls[i]==' y ')//The array element with the content is ' Y ' is labeled as prime number{printf("%5d", i); cnt++;if(! (cnt% -))printf("\ n");    } i++; }printf("\n0-%d has%d prime numbers.\n", Flen, CNT);Delete(FLS);//release of memory allocated by GETPRIMESLESSN    return 0;}/ * END main * /

Get a C + + implementation of optimization filtering method for prime numbers less than n