Java实现整数分解质因数的方法示例

import java.util.Scanner;
public class Main {
  public static boolean isPrime(int i)
  {
    boolean isPrime = true;
    //除到i的平方根就可以判断
    for (int j = 2; j<=Math.sqrt(i);j++)
    {
      if(i%j==0)
        isPrime = false;
    }
    return isPrime;
  }
  public static void main(String[] args) {
    // TODO Auto-generated method stub
    System.out.println(" - 分解质因数测试：");
    Scanner in = new Scanner(System.in);
    int n = in.nextInt();
    String out = n + "=";
    if(isPrime(n))
    {
      out = out+ n;
    }
    else
    {
      while(n!=1)
      {
        for(int j=2;j<=n;j++)
        {
          //对最后一个进行特殊处理
          if(j==n)
          {
            n=1;
            out = out + j;
            break;
          }
          if(n%j==0)
          {
            n=n/j;
            out = out + j+"x";
            break;
          }
        }
      }
    }
    System.out.println(out);
    in.close();
  }
}