字符串和十六进制互相转换

3170阅读　0评论2015-05-06　QLL999
分类：C/C++


点击(此处)折叠或打开

  1. #include <stdio.h>
  2. #include <string.h>

  4. int strToHex(char *ch, char *hex);
  5. int hexToStr(char *hex, char *ch);
  6. int hexCharToValue(const char ch);
  7. char valueToHexCh(const int value);

  9. int main(int argc, char *argv[])
  10. {
  11.     char ch[1024];
  12.     char hex[1024];
  13.     char result[1024];
  14.     char *p_ch = ch;
  15.     char *p_hex = hex;
  16.     char *p_result = result;

  18.     printf("please input the string:");
  19.     scanf("%s",p_ch);

  21.     strToHex(p_ch,p_hex);

  23.     printf("the hex is:%s\n",p_hex);
  24.     hexToStr(p_hex, p_result);
  25.     printf("the string is:%s\n", p_result);
  26.     return 0;
  27. }

  29. int strToHex(char *ch, char *hex)
  30. {
  31.     int high,low;
  32.     int tmp = 0;
  33.     if(ch == NULL || hex == NULL)
  34.     {
  35.         return -1;
  36.     }

  38.     if(strlen(ch) == 0)
  39.     {
  40.         return -2;
  41.     }

  43.     while(*ch)
  44.     {
  45.         tmp = (int)*ch;
  46.         high = tmp >> 4;
  47.         low = tmp & 15;
  48.         *hex++ = valueToHexCh(high); //先写高字节
  49.         *hex++ = valueToHexCh(low); //其次写低字节
  50.         ch++;
  51.     }

  53.     *hex = '\0';
  54.     return 0;
  55. }

  57. int hexToStr(char *hex, char *ch)
  58. {
  59.     int high,low;
  60.     int tmp = 0;

  62.     if(hex == NULL || ch == NULL)
  63.     {
  64.         return -1;
  65.     }

  67.     if(strlen(hex) %2 == 1)
  68.     {
  69.         return -2;
  70.     }

  72.     while(*hex)
  73.     {
  74.         high = hexCharToValue(*hex);
  75.         if(high < 0)
  76.         {
  77.             *ch = '\0';
  78.             return -3;
  79.         }
  80.         
  81.         hex++; //指针移动到下一个字符上

  83.         low = hexCharToValue(*hex);

  85.         if(low < 0)
  86.         {
  87.             *ch = '\0';
  88.             return -3;
  89.         }

  91.         tmp = (high << 4) + low;
  92.         *ch++ = (char)tmp;
  93.         hex++;
  94.     }
  95.     *ch = '\0';
  96.     return 0;
  97. }



  101. int hexCharToValue(const char ch)
  102. {
  103.     int result = 0;

  105.     //获取16进制的高字节位数据
  106.     if(ch >= '0' && ch <= '9')
  107.     {
  108.         result = (int)(ch - '0');
  109.     }
  110.     else if(ch >= 'a' && ch <= 'z')
  111.     {
  112.         result = (int)(ch - 'a') + 10;
  113.     }
  114.     else if(ch >= 'A' && ch <= 'Z')
  115.     {
  116.         result = (int)(ch - 'A') + 10;
  117.     }
  118.     else
  119.     {
  120.         result = -1;
  121.     }

  123.     return result;
  124. }

  126. char valueToHexCh(const int value)
  127. {
  128.     char result = '\0';
  129.     if(value >= 0 && value <= 9)
  130.     {
  131.         result = (char)(value + 48); //48为ascii编码的‘0’字符编码值
  132.     }
  133.     else if(value >= 10 && value <= 15)
  134.     {
  135.         result = (char)(value - 10 + 65); //减去10则找出其在16进制的偏移量，65为ascii的'A'的字符编码值
  136.     }
  137.     else
  138.     {
  139.         ;
  140.     }

  142.     return result;
  143. }

上一篇：vim编辑退出后乱码问题解决
下一篇：NTP时间服务器列表