real.cpp

   1 /* Returns the real part of complex z
   2
   3         z               real(z)
   4         -               -------
   5
   6         a + i b         a
   7
   8         exp(i a)        cos(a)
   9 */
  10
  11 #include "stdafx.h"
  12 #include "defs.h"
  13
  14 void
  15 eval_real(void)
  16 {
  17         push(cadr(p1));
  18         eval();
  19         real();
  20 }
  21
  22 void
  23 real(void)
  24 {
  25         save();
  26         rect();
  27         p1 = pop();
  28         push(p1);
  29         push(p1);
  30         conjugate();
  31         add();
  32         push_integer(2);
  33         divide();
  34         restore();
  35 }
  36
  37 #if SELFTEST
  38
  39 static char *s[] = {
  40
  41         "real(a+i*b)",
  42         "a",
  43
  44         "real(1+exp(i*pi/3))",
  45         "3/2",
  46
  47         "real(i)",
  48         "0",
  49
  50         "real((-1)^(1/3))",
  51         "1/2",
  52 };
  53
  54 void
  55 test_real(void)
  56 {
  57         test(__FILE__, s, sizeof s / sizeof (char *));
  58 }
  59
  60 #endif