Convert character from UTF-8 to ISO-8859-1 manually

Question

I have the character \"ö\". If I look in this UTF-8 table I see it has the hex value F6. If I look in the Unicode table I see that \"ö\" has the indices E

Answer 1

unsigned cha_latin2utf8(unsigned char *dst, unsigned cha)
{
if (cha <  0x80)  { *dst = cha; return 1; }
    /* all 11 bit codepoints (0x0 -- 0x7ff)
      ** fit within a 2byte utf8 char
      ** firstbyte = 110 +xxxxx := 0xc0 + (char>>6) MSB
      ** second    = 10 +xxxxxx := 0x80 + (char& 63) LSB
      */
    *dst++ = 0xc0 | (cha >>6) & 0x1f; /* 2+1+5 bits */
    *dst++ = 0x80 | (cha) & 0x3f; /* 1+1+6 bits */

return 2; /* number of bytes produced */
}

To test it:

#include 
int main (void)
{
char buff[12];

cha_latin2utf8 ( buff, 0xf6);

fprintf(stdout, "%02x %02x\n"
    , (unsigned) buff[0] & 0xff
    , (unsigned) buff[1] & 0xff );

return 0;
}

The result:

c3 b6