自己怎么实现Integer.toHexString(int i)函数

[beibei58]

今天面试的时候遇到一个这样的问题！有点不解！新手！
就是自己怎么实现Integer.toHexString(int i)函数

[柯本]

由C改过来的,参考下:

public static String toHexString(int input)
	{
		String output="";
		int base=16;
		int c=0;
		int lowbit=0;
		
		 base >>= 1;
		  do {
		    lowbit = input & 1;
		    input = (input >> 1) & 0xffffffff;
		    c = ((input % base) << 1) + lowbit;
		    if(c < 10) 
		    	c += '0'; 
		     else c +='A';
		    output+=(char)c;
		    } while((input/=base)!=0);
		  
		  StringBuffer sb=new StringBuffer(output);

		  output= sb.reverse().toString();
		
		return output;
	}

[打油的程序员]

public class Test{
    public static void main(String[] args) {
        System.out.println(convert(1234));        
    }
    public static String  convert(Integer i){//i>0
	char[] upperCharacter = "0123456789ABCDEF".toCharArray();
	String result = "" ; 
	while(i!=0){
	    result=upperCharacter[i%16]+result;
	    i/=16;
	}
	return result;	
    }
}

刚才回复了一个类似的贴：http://topic.csdn.net/u/20111010/23/08e756ba-392a-4d4d-b251-1c0dac20a0cb.html?21147
我只把它改了几个数字

[打油的程序员]

public class Test{
    public static void main(String[] args) {
        System.out.println(toHexString(-100));        
    }
    public static String  toHexString(Integer i){//i>0
	boolean b = false;//是正否为负数
	if(i==0)return  "0";
	else if(i<0) {
	    b = true;//是负数
	    i=-i;
	}
	char[] hex = "0123456789ABCDEF".toCharArray();
	String result = "" ; 
	while(i!=0){
	    result=hex[i%16]+result;
	    i/=16;
	}
	if(b) result="-"+result;
	return result;	
    }
}

[打油的程序员]

一楼的改为这样 就可以转换负数了：

public class Test {
    public static void main(String[] args) {
	System.out.println(toHexString(-100));
    }
    public static String toHexString(int input) {
	boolean b = false;//是正否为负数
	if (input < 0) {
	    b = true;
	    input = -input;
	}
	String output = "";
	int base = 16;
	int c = 0;
	int lowbit = 0;
	base >>= 1;
	do {
	    lowbit = input & 1;
	    input = (input >> 1) & 0xffffffff;
	    c = ((input % base) << 1) + lowbit;
	    if (c < 10)
		c += '0';
	    else
		c += 'A';
	    output += (char) c;
	} while ((input /= base) != 0);

	StringBuffer sb = new StringBuffer(output);

	output = sb.reverse().toString();
	if (b)
	    output = "-" + output;
	return output;
    }
}