std::set hello world example

userland/cpp/set.cpp

@@ -0,0 +1,39 @@
+// https://cirosantilli.com/linux-kernel-module-cheat#cpp
+
+#include <cassert>
+#include <set>
+
+int main() {
+    std::set<int> s{0, 2};
+
+    // Insert another element.
+    auto insert_ret = s.insert(3);
+    assert(insert_ret.first == s.find(3));
+    assert(insert_ret.second == true);
+
+    // Insert something already there, second of return is false.
+    insert_ret = s.insert(3);
+    assert(insert_ret.second == false);
+
+    // Check if a value is present.
+    auto zero = s.find(0);
+    assert(zero != s.end());
+    assert(*zero == 0);
+
+    // Now for a value that is not present.
+    auto one = s.find(1);
+    assert(one == s.end());
+
+#if __cplusplus > 201703L
+    // In C++20 we finally have a .contains() to avoid the end mess!
+    assert(s.contains(0));
+    assert(!s.contains(1));
+#endif
+
+    // Remove an element.
+    // Was present, so return 1;
+    assert(s.erase(0) == 1);
+    assert(s.find(0) == s.end());
+    // Not present, return 0.
+    assert(s.erase(0) == 0);
+}