how to convert a hex character in ascii character

char hexToAscii(char hex_char)
{
switch(hex_char) {
case 0:
return '0';
case 1:
return '1';
case 2:
return '2';
case 3:
return '3';
case 4:
return '4';
case 5:
return '5';
case 6:
return '6';
case 7:
return '7';
case 8:
return '8';
case 9:
return '9';
case 10:
return 'a';
case 11:
return 'b';
case 12:
return 'c';
case 13:
return 'd';
case 14:
return 'e';
case 15:
return 'f';
default:
return '?';
}

}