How to output Greek letters commonly used in mathematics and

Question

hi friend,
 I want to output some special character graphics.

This is the topic:http://en.wikipedia.org/wiki/Code_page_437#Difference_from_ASCII

Here is the code I tried.It does not seem to achieve the desired effect:
#include <stdio.h>
const long int Sigma=0x03A3;   // Math symbol
const long int Smiley=0x263A; //  Special graphic characters
void main(void)
{
 
printf("%x\n",Sigma); // it can't output graphics
printf("%x\n",Smiley);
}

Thank.