java - How can I get largest prime factors between two numbers and store them in an array? -

i've been asked solve question:

write function takes 2 numbers n1 , n2 input (with n2>n1) , returns array of largest prime factors corresponding each number between n1 , n2.

my attempt shown below, code not working properly. not iterating n1 n2. how can right?

public static class a{         static int testcase1=5;         static int testcase2=10;          public static void main(string args[]){             testinstance = new a();             int[] result = testinstance.getlpfd(testcase1,testcase2);             system.out.print("{");             (int i=0;i<result.length;i++){                 if (i>0)                     system.out.print(",");                 system.out.print(result[i]);             }             system.out.println("}");         }          public int[] getlpfd(int n1,int n2){             int current=0;             int[] factors = new int[20];             for(int j=n1;j<=n2;j++){                 (int = 2; <= j; i++){                     while(j % == 0){                         factors[current]=i;                         j /= i;                         current++;                     }                 }             }                        return factors;         }     } } 

it's easiest separate task of finding factors task of writing largest factor. here function find factors:

function factors(n)     f, fs := 2, []     while f * f <= n         while n % f == 0             insert f @ head of fs             n := n / f         f := f + 1     if n > 1         insert n @ head of fs     return fs 

that returns factors of n in descending order, largest factor @ head of list. easy accumulate list of largest prime factors of range:

function lpf(lo, hi)     result := makearray(0 .. hi-lo)     n lo hi         result[n-lo] := head(factors(n))     return result 

i'll leave translate java.

if range large, variant of sieve of eratosthenes faster computing factors.