// define, cout, printf<br>ประกาศ และพิมพ์ด้วย cout
/* http://www.thaiall.com/tc */
#include <stdio.h>
#include <iostream.h>
#include <conio.h>
#define p 3.1415926
#define n "Number = "
void main()
{
  clrscr();
  cout << p << "\n";           // 3.141593
  printf("%5.4f \n",p);        // 3.1416
  printf("%s %5.9f \n",n,p);   // Number = 3.141592600
  getch();
}