C语言极简 小写转大写

#include
#include

void lower2UpCase(char *buf){
    char c;
    while(*buf != '\0'){
        c = *buf;
        if (c>='a' && c <= 'z')
          {
            c ^= 32;
            *buf = c;
          }
          buf ++;
    }
}

int main()
{
    char szbuf[18] = "c4:f6:c5:82:11:fa";
    printf("before : %s\n",szbuf);
    lower2UpCase(szbuf);
    printf("after : %s\n",szbuf);
}