Algorithm for solving prime numbers

1. Loop nesting, the outer loop is from 1-1000 of the number I (1 excluded, which you should understand), the inner layer is the number I of the prime judgment.

2. Prime number: There is no other factor except 1 and itself. It can also be understood that except for 1 and itself, the remainder of the number is not 0.

3. So the inner loop is used from 2 to the square root of I (rounding) in order to find the remainder, because to the square root, and then increase the divisor, the quotient is less than the square root, equal to the divisor previously taken. So the square root after no longer forget.

1 classTest {2 3  Public StaticBoolean IsPrime (intN) {4      for(inti = 2; I <= math.sqrt (n); i++) { 5         if(n% i = = 0) {6         return false;7         } 8     }9     return true;Ten } One  A  Public Static voidMain (string[] args) { -  -  intLen = 1000; the  //1 is neither a prime nor a composite, and 2 is the smallest even prime. -   for(inti = 2; I <= Len; i + +) { -  if(Test.isprime (i)) { -System.out.print (i + "")); +              } -          } +     }  A}

Algorithm for solving prime numbers