Serial C++ version of pi added

.gitignore

@@ -17,6 +17,7 @@ Exercises/Exercise01/Cpp/DeviceInfo
 Exercises/Exercise03/Cpp/vadd
 Exercises/Exercise04/Cpp/vadd
 Exercises/Exercise05/Cpp/vadd
+Exercises/Exercise08/Cpp/pi
 
 Solutions/Exercise04/C/vadd_chain
 Solutions/Exercise05/C/vadd_abc

Exercises/Exercise08/Cpp/Makefile

@@ -0,0 +1,15 @@
+CC=g++
+
+CCFLAGS=-O3 -std=c++11 -std=gnu++11
+
+LIBS = -lm
+
+CPP_COMMON = ../../Cpp_common
+
+INC = -I $(CPP_COMMON)
+
+pi: pi.cpp
+	$(CC) $^ $(INC) $(CCFLAGS) $(LIBS) -o $@
+
+clean:
+	rm -f pi

Exercises/Exercise08/Cpp/pi.cpp

@@ -0,0 +1,44 @@
+/*
+
+This program will numerically compute the integral of
+
+                  4/(1+x*x) 
+				  
+from 0 to 1.  The value of this integral is pi -- which 
+is great since it gives us an easy way to check the answer.
+
+The is the original sequential program.  It uses the timer
+from the OpenMP runtime library
+
+History: Written by Tim Mattson, 11/99.
+         Ported to C++ by Tom Deakin, August 2013
+
+*/
+
+#include "util.hpp"
+
+#include <cstdio>
+static long num_steps = 100000000;
+double step;
+extern double wtime();   // returns time since some fixed past point (wtime.c)
+
+
+int main ()
+{
+    int i;
+    double x, pi, sum = 0.0;
+
+
+    step = 1.0/(double) num_steps;
+
+    util::Timer timer;
+
+    for (i=1;i<= num_steps; i++){
+        x = (i-0.5)*step;
+        sum = sum + 4.0/(1.0+x*x);
+    }
+
+    pi = step * sum;
+    double run_time = static_cast<double>(timer.getTimeMilliseconds()) / 1000.0;
+    printf("\n pi with %ld steps is %lf in %lf seconds\n", num_steps, pi, run_time);
+}