Merge pull request #31 from k06a/feature/default-argument

Add optional defaultValue argument for firstOrDefault and lastOrDefault

include/boolinq/boolinq.h

@@ -540,22 +540,22 @@ namespace boolinq {
             return Linq<S, T>(*this).next();
         }
 
-        T firstOrDefault(std::function<bool(T)> predicate) const
+        T firstOrDefault(std::function<bool(T)> predicate, T defaultValue = T()) const
         {
             try {
                 return where(predicate).next();
             }
             catch (LinqEndException &) {}
-            return T();
+            return defaultValue;
         }
 
-        T firstOrDefault() const
+        T firstOrDefault(T defaultValue = T()) const
         {
             try {
                 return Linq<S, T>(*this).next();
             }
             catch (LinqEndException &) {}
-            return T();
+            return defaultValue;
         }
 
         T last(std::function<bool(T)> predicate) const
@@ -578,18 +578,18 @@ namespace boolinq {
             return last([](T /*value*/) { return true; });
         }
 
-        T lastOrDefault(std::function<bool(T)> predicate) const
+        T lastOrDefault(std::function<bool(T)> predicate, T defaultValue = T()) const
         {
-            T res = T();
+            T res = defaultValue;
             where(predicate).for_each([&res](T value) {
                 res = value;
             });
             return res;
         }
 
-        T lastOrDefault() const
+        T lastOrDefault(T defaultValue = T()) const
         {
-            return lastOrDefault([](T  /*value*/) { return true; });
+            return lastOrDefault([](T  /*value*/) { return true; }, defaultValue);
         }
 
         // Export to containers

test/FirstTest.cpp

@@ -37,3 +37,11 @@ TEST(First, NoneElements)
     EXPECT_EQ(0, from(src).firstOrDefault());
     EXPECT_EQ(0, from(src).firstOrDefault([](int a){return a%2 == 0;}));
 }
+
+TEST(First, NoneElementsWithArg)
+{
+    std::vector<int> src = {};
+
+    EXPECT_EQ(2, from(src).firstOrDefault(2));
+    EXPECT_EQ(3, from(src).firstOrDefault([](int a){return a%2 == 0;}, 3));
+}

test/LastTest.cpp

@@ -37,3 +37,10 @@ TEST(Last, NoneElements)
     EXPECT_EQ(0, from(src).lastOrDefault());
     EXPECT_EQ(0, from(src).lastOrDefault([](int a){return a%2 == 0;}));
 }
+
+TEST(Last, NoneElementsWithArgument) {
+    std::vector<int> src = {};
+
+    EXPECT_EQ(2, from(src).lastOrDefault(2));
+    EXPECT_EQ(3, from(src).lastOrDefault([](int a) { return a % 2 == 0; }, 3));
+}