replaces testfilter with filter_examples

ryanhaining · ryanhaining · commit 40255292c177 · 2015-04-18T20:03:28.000-07:00
diff --git a/examples/filter_examples.cpp b/examples/filter_examples.cpp
@@ -0,0 +1,58 @@
+#include <filter.hpp>
+
+#include <vector>
+#include <iostream>
+
+bool greater_than_four(int i) {
+    return i > 4;
+}
+
+class LessThanValue {
+    private:
+        int compare_val;
+
+    public:
+        LessThanValue() = delete;
+        LessThanValue(int v) : compare_val(v) { }
+
+        bool operator() (int i) {
+            return i < this->compare_val;
+        }
+};
+
+
+int main() {
+    std::vector<int> ns{1, 5, 6, 0, 7, 2, 3, 8, 3, 0, 2, 1};
+    std::cout << "ns = { ";
+    for (auto&& i : ns) {
+        std::cout << i << ' ';
+    }
+    std::cout << "}\n";
+
+    std::cout << "Greater than 4 (function pointer)\n";
+    for (auto&& i : iter::filter(greater_than_four, ns)) {
+        std::cout << i << '\n';
+    }
+
+    std::cout << "Less than 4 (lambda)\n";
+    for (auto&& i : iter::filter([] (const int i) { return i < 4; }, ns)) {
+        std::cout << i << '\n';
+    }
+
+    LessThanValue lv(4);
+    std::cout << "Less than 4 (callable object)\n";
+    for (auto&& i : iter::filter(lv, ns)) {
+        std::cout << i << '\n';
+    }
+
+    // filter(seq) with no predicate uses the truthiness of the values
+    std::cout << "Nonzero ints filter(ns)\n";
+    for (auto&& i : iter::filter(ns)) {
+        std::cout << i << '\n';
+    }
+
+    std::cout << "odd numbers\n";
+    for (auto&& i : iter::filter([] (const int i) {return i % 2;}, ns)) {
+        std::cout << i << '\n';
+    }
+}
