Add source files

exple-cmake-build/exple-expr.hpp

+#include "exple-add.h"
+#include "exple-mul.h"
+
+namespace exple
+{
+  int add_and_mul( int a, int b, int c);
+}
+
+int exple::add_and_mul( int a, int b, int c)
+{
+  return exple::mul(exple::add(a, b), c);
+}

exple-cmake-build/main.cpp

+#include "exple-expr.hpp"
+
+#include <stdio.h>
+
+int main()
+{
+
+  int a = 2;
+  int b = 3;
+  int c = 4;
+  printf("Multiplication of sum of %i and %i by %i is... %i", a, b, c, exple::add_and_mul(2, 3, 4));
+
+  return 0;
+}