java学习进制转换之查表法

10进制转16进制,以及10进制转2进制,还有10进制转8进制,这些转换如果按照常规思路的话,会灰常的麻烦。

我们来看一下 10进制转16进制:

假如这里有一个十进制数字:35,我们的需求就是把这个35转成16进制的。

思路:先把35转换成二进制,然后二进制再转换16进制。

代码:

class SearchTable
{
	
	public static void main(String[]  args)
	{

		String[] s = searchTable(35,3,7);

		/**
		*
		*for(int i = 0;  i< arr.length ; i++)
		*{
		*
		*	System.out.println(arr[i]);
		*
		*}
		*/
		for(int i = 0; i<8 ; i++)
		{

			System.out.print(s[i]);

		}
		

	}

	public static String[] searchTable(int num,int offset,int mask)
	{

		String[] table = {"","1","2","3","4","5","6","7","8","9","a","b","c","d","e"};

		String[] output = new String[8];

		int [] arrtemp = new int[8];

		for(int i = arrtemp.length-1 ; i>=0 ; i--){

			arrtemp[i] = num&mask;

			num = num>>>offset;

			output[i] =table[arrtemp[i]];

		}

		return output;
	}

}

温馨提示,当写程序的时候尽量保证一个量变化否则,会把自己绕进去的。

/**
*反面示例
*/
class SearchTable
{
	
	public static void main(String[]  args)
	{

		String s = searchTable(35,3,7);

		/**
		*
		*for(int i = 0;  i< arr.length ; i++)
		*{
		*
		*	System.out.println(arr[i]);
		*
		*}
		*/
		System.out.print(s);

	}

	public static String searchTable(int num,int offset,int mask)
	{

		String[] table = {"","1","2","3","4","5","6","7","8","9","a","b","c","d","e"};

		String output = "";

		int [] arrtemp = new int[8];

		for(int i =0  ; i<arrtemp.length-1 ; i++){

			arrtemp[i] = num&mask;

			num = num>>>offset;
			System.out.println("---"+i+"--");
			System.out.println(arrtemp[7-i]);
			System.out.println(table[arrtemp[i]]);
			System.out.println("---"+i+"--end");	

			output += table[arrtemp[i]];

		}

		return output;

	}

}

  

原文地址:https://www.cnblogs.com/sunchuanzhen/p/3326216.html