From 7f67471e7b5a1aee83b032e2ac8e09ea1dfac097 Mon Sep 17 00:00:00 2001
From: neingeist <neingeist@bl0rg.net>
Date: Sun, 13 Apr 2014 10:03:09 +0200
Subject: [PATCH] add accumulate example

---
 .gitignore     |  1 +
 CMakeLists.txt |  1 +
 accumulate.cpp | 45 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+)
 create mode 100644 accumulate.cpp

diff --git a/.gitignore b/.gitignore
index 9cc68db..1c58de3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,4 @@ typetest
 unique_ptr
 list-initializers
 array-bounds
+accumulate
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 817877e..9b97923 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,3 +8,4 @@ add_executable(auto_ptr auto_ptr.cpp)
 add_executable(unique_ptr unique_ptr.cpp)
 add_executable(list-initializers list-initializers.cpp)
 add_executable(array-bounds array-bounds.cpp)
+add_executable(accumulate accumulate.cpp)
diff --git a/accumulate.cpp b/accumulate.cpp
new file mode 100644
index 0000000..95062a2
--- /dev/null
+++ b/accumulate.cpp
@@ -0,0 +1,45 @@
+// http://www.cplusplus.com/reference/numeric/accumulate/
+
+#include <cassert>
+#include <iostream>
+
+#include <functional>   // std::minus
+#include <numeric>      // std::accumulate
+
+int myfunction (int x, int y) { return x+2*y; }
+
+struct myclass {
+  int operator()(int x, int y) { return x+3*y; }
+} myobject;
+
+int main() {
+  int init = 100;
+  int numbers[] = {10,20,30};
+  int res;
+
+  std::cout << "using default accumulate: ";
+  res = std::accumulate(numbers, numbers+3, init);
+  std::cout << res;
+  assert(res == 100+10+20+30);
+  std::cout << '\n';
+
+  std::cout << "using functional's minus: ";
+  res = std::accumulate(numbers, numbers+3, init, std::minus<int>());
+  std::cout << res;
+  assert(res == 100-10-20-30);
+  std::cout << '\n';
+
+  std::cout << "using custom function: ";
+  res = std::accumulate(numbers, numbers+3, init, myfunction);
+  std::cout << res;
+  assert(res == 100+20+40+60);
+  std::cout << '\n';
+
+  std::cout << "using custom object: ";
+  res = std::accumulate(numbers, numbers+3, init, myobject);
+  std::cout << res;
+  assert(res == 100+30+60+90);
+  std::cout << '\n';
+
+  return 0;
+}