Apply several clang-tidy fixes

poly2tri/common/shapes.cc

@@ -86,13 +86,11 @@ void Triangle::MarkNeighbor(Triangle& t)
 void Triangle::Clear()
 {
     Triangle *t;
-    for( int i=0; i<3; i++ )
-    {
-        t = neighbors_[i];
-        if( t != nullptr )
-        {
-            t->ClearNeighbor( this );
-        }
+    for (auto& neighbor : neighbors_) {
+      t = neighbor;
+      if (t != nullptr) {
+        t->ClearNeighbor(this);
+      }
     }
     ClearNeighbors();
     points_[0]=points_[1]=points_[2] = nullptr;
@@ -410,4 +408,4 @@ bool IsDelaunay(const std::vector<p2t::Triangle*>& triangles)
   return true;
 }
 
-}
+} // namespace p2t

poly2tri/sweep/advancing_front.cc

@@ -107,4 +107,4 @@ AdvancingFront::~AdvancingFront()
 {
 }
 
-}
+} // namespace p2t

poly2tri/sweep/sweep.cc

@@ -815,10 +815,9 @@ void Sweep::FlipScanEdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle&
 Sweep::~Sweep() {
 
     // Clean up memory
-    for(size_t i = 0; i < nodes_.size(); i++) {
-        delete nodes_[i];
+    for (auto& node : nodes_) {
+      delete node;
     }
-
 }
 
 } // namespace p2t

poly2tri/sweep/sweep_context.cc

@@ -194,17 +194,13 @@ SweepContext::~SweepContext()
     delete af_middle_;
     delete af_tail_;
 
-    typedef std::list<Triangle*> type_list;
-
-    for(type_list::iterator iter = map_.begin(); iter != map_.end(); ++iter) {
-        Triangle* ptr = *iter;
-        delete ptr;
+    for (auto ptr : map_) {
+      delete ptr;
     }
 
-     for(unsigned int i = 0; i < edge_list.size(); i++) {
-        delete edge_list[i];
+    for (auto& i : edge_list) {
+      delete i;
     }
-
 }
 
 } // namespace p2t