Use array subscripts to correspond to prime numbers within a specified range, and take advantage of a Boolean type value flag that is a prime number

1  Packagecom.jdk7.chapter4;2 3  Public classPrimenumber {4      Public voidGetprime (intrange) {5         Boolean[] SourceData = This. IsPrime (range);6         7         if(! (sourcedata==NULL)){8             intSize =sourcedata.length;9integer[] Resultdata =NewInteger[size];Ten             //Number definition to be placed outside of the increment operation loop, otherwise it may not achieve the desired effect One             intNumber = 0; A              for(inti=1;i<size;i++){ -                 if(Sourcedata[i]) { -Resultdata[i] =i; theSystem.out.print ("prime number [" +i+ "]:" +resultdata[i].tostring () + ""); -                     if(++number% 10 = = 0){ - System.out.println (); -                     } +                 } -             } + System.out.println (); ASYSTEM.OUT.PRINTLN ("Total number of prime numbers:" +Number ); at         } -     } -      -     Private Boolean[] IsPrime (intrange) { -         Boolean[] Tag =New Boolean[Range+1]; -         if(range<=0) {return NULL;} in          for(inti=1;i<range+1;i++){ -             if(i==1){ toTag[i] =false; +}Else{ -Tag[i] =true; the                 } *         } $         //assuming Tag[i] is a prime number, the multiples of prime numbers must be non-primePanax Notoginseng         intsqrt = (int) math.sqrt (range); -          for(inti=1;i<=sqrt;i++){ the             if(Tag[i]) { +                  for(intj= (2 * i); j<=range;j+=i) { ATAG[J] =false; the                 } +             } -         } $         returntag; $     } -}

1  Packagecom.jdk7.chapter4;2 3  Public classPrimenumbertest {4      Public Static voidMain (string[] args) {5Primenumber pn =NewPrimenumber ();6         intRange = 100;7 pn.getprime (range);8     }9 }Ten  One Execution Result: APrime number [2]: 2 primes [3]: 3 primes [5]: 5 primes [7]: 7 primes [11]: 11 primes [13]: 13 primes [17]: 17 primes [19]: 19 primes [23]: 23 primes [29]: 29 -Prime number [31]: 31 primes [37]: 37 primes [41]: 41 primes [43]: 43 primes [47]: 47 primes [53]: 53 primes [59]: 59 primes [61]: 61 primes [67]: 67 primes [71]: 71 -Prime number [73]: 73 primes [79]: 79 primes [83]: 83 primes [89]: 89 primes [97]: 97 theTotal number of prime numbers: 25

Use array subscripts to correspond to prime numbers within a specified range, and take advantage of a Boolean type value flag that is a prime number