Add pi.awk program in MPFR chapter.

1 files changed, 18 insertions, 0 deletions

diff --git a/awklib/eg/prog/pi.awk b/awklib/eg/prog/pi.awk
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+# pi.awk --- compute the digits of pi
+#
+# Katie Wasserman, katie@wass.net
+# August 2014
+
+BEGIN {
+    digits = 100000
+    two = 2 * 10 ^ digits
+    pi = two
+    for (m = digits * 4; m > 0; --m) {
+        d = m * 2 + 1
+        x = pi * m
+        div(x, d, result)
+        pi = result["quotient"]
+        pi = pi + two
+    }
+    print pi
+}