c語言unsigned char轉成字符串

    unsigned char MD[16];
    MD5((unsigned char*)p,statbuf.st_size,MD);//獲得MD5值 適用於mmap傳輸
    char buffer[1000]={0};
    for(int i = 0; i < 16; i++)  {  
        //格式化輸str,每unsigned char 轉換字符占兩位置%x寫輸%X寫輸  
        sprintf(buffer + i*2, "%02x", MD[i]);  
    }