字符转化

byteToHexStr.cpp

#include <string>
  std::string byteToHexStr(unsigned char byte_arr[], int arr_len)
  {	
 	 std::string hexstr;
 	 for (int i=0;i<arr_len;i++)
 	 {
 		 char hex1;
 		 char hex2;
 		 int value=byte_arr[i]; //直接将unsigned char赋值给整型的值，系统会自动强制转换
 		 int v1=value/16;
 		 int v2=value % 16;
 
 		 //将商转成字母
 		 if (v1>=0&&v1<=9)
 			 hex1=(char)(48+v1);
 		 else
 			 hex1=(char)(55+v1);
 
 		 //将余数转成字母
 		 if (v2>=0&&v2<=9)
 			 hex2=(char)(48+v2);
 		 else
 			 hex2=(char)(55+v2);
 
 		 //将字母连接成串
 		 hexstr=hexstr+hex1+hex2;
 	 }
 	 return hexstr;
  }