C-switch case之如何巧妙判断范围区域

#include <stdio.h>

int main()
{    
    unsigned char buf[6]={0x00,0x07,0x11,0x60,0x61,0x66};
    
    for(int i=0;i<6;i++)
    switch(buf[i])
    {
        case 0x00 ... 0x10: printf(\"buf[%d] is 0x0 ~0x10\\n\",i);  break;
        case 0x11 ... 0x20: printf(\"buf[%d] is 0x11~0x20\\n\",i);  break;
        case 0x30 ... 0x60: printf(\"buf[%d] is 0x30~0x60\\n\",i);  break;
        case 0x61 ... 0xff: printf(\"buf[%d] is 0x61~0xff\\n\",i);  break;
    } 
} 

#include <stdio.h>


int main()
{    
    char buf[6][6]={\"0xff\",\"0X02\",\"0X1f\",\"0xf1\",\"0xa1\",\"0Xb0\"};

    for(int i=0;i<6;i++)
    if(buf[i][0]==\'0\'&&(buf[i][1]==\'x\' || buf[i][1]==\'X\'))    //匹配前缀
    {
        unsigned char val=0;
        int err=0; 
        for(int j=2;j<4;j++)
        switch(buf[i][j]) 
        {
            case \'0\' ... \'9\' :   val= val*16 + (buf[i][j]-\'0\'); break;
            case \'a\' ... \'f\' :   val= val*16 + (buf[i][j]-\'a\'+10); break;
            case \'A\' ... \'F\' :   val= val*16 + (buf[i][j]-\'A\'+10); break;
            default :  err =1;  break;
        }   

        if(!err)    
            printf(\"buf[%d]  = 0X%02X\\n\",i,val);
        else
            printf(\"buf[%d]  ERR \\n\",i); 
    }
    else
        printf(\"buf[%d]  ERR \\n\",i); 
    
}