Documenting algorithm/set_union

algorithm/set_union.md

@@ -0,0 +1,32 @@
+# set_union
+
+**Description** : Constructs a sorted range beginning in the location passed by result with the set union of the two sorted ranges `[first1, last1)` and `[first2, last2)`.
+
+**Example**:
+```cpp
+    std::vector<int> v1 {3, 1, 5};
+    std::vector<int> v2 {1, 0};
+
+    // the destination needs to fit all merged values, we'll prune the extra elements later
+    std::vector<int> destination(v1.size() + v2.size());
+
+    // set_union requires sorted ranges
+    std::sort(v1.begin(), v1.end());
+    std::sort(v2.begin(), v2.end());
+
+    // returns iterator to the end of the constructed range
+    auto it = std::set_union(v1.begin(), v1.end(),  // first range 
+                             v2.begin(), v2.end(),  // second range
+                             destination.begin());
+
+    // prune extra values
+    destination.resize(it - destination.begin()); 
+
+    // destination is now {0, 1, 3, 5}
+    for (auto value : destination) { 
+        std::cout << value << " "; 
+    }
+
+```
+**[See Sample code](snippets/algorithm/set_union.cpp)**
+**[Run Code](https://rextester.com/LFXB93097)**

snippets/algorithm/set_union.cpp

@@ -0,0 +1,37 @@
+ /*
+    Author : Thamara Andrade
+    Date : Date format 02/09/2019
+    Time : Time format 02:00
+    Description : Checks if a range is included in another range.
+*/
+
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+int main()
+{
+    std::vector<int> v1 {3, 1, 5};
+    std::vector<int> v2 {1, 0};
+
+    // the destination needs to fit all merged values, we'll prune the extra elements later
+    std::vector<int> destination(v1.size() + v2.size());
+
+    // set_union requires sorted ranges
+    std::sort(v1.begin(), v1.end());
+    std::sort(v2.begin(), v2.end());
+
+    // returns iterator to the end of the constructed range
+    auto it = std::set_union(v1.begin(), v1.end(),  // first range 
+                             v2.begin(), v2.end(),  // second range
+                             destination.begin());
+
+    // prune extra values
+    destination.resize(it - destination.begin()); 
+
+    // destination is now {0, 1, 3, 5}
+    for (auto value : destination) { 
+        std::cout << value << " "; 
+    }
+    return 0;
+}