diff --git a/src/stt/include/stt/SteinerTreeBuilder.h b/src/stt/include/stt/SteinerTreeBuilder.h
index 31671e520cf..3ae542abccc 100644
--- a/src/stt/include/stt/SteinerTreeBuilder.h
+++ b/src/stt/include/stt/SteinerTreeBuilder.h
@@ -89,7 +89,7 @@ class SteinerTreeBuilder
  private:
   int computeHPWL(odb::dbNet* net);
 
-  static constexpr int flute_accuracy = 3;
+  static constexpr int kFluteAccuracy = 3;
   float alpha_;
   std::map<const odb::dbNet*, float> net_alpha_map_;
   std::pair<int, float> min_fanout_alpha_;
diff --git a/src/stt/src/LinesRenderer.cpp b/src/stt/src/LinesRenderer.cpp
index 336c4676304..628bb32e7f1 100644
--- a/src/stt/src/LinesRenderer.cpp
+++ b/src/stt/src/LinesRenderer.cpp
@@ -8,7 +8,7 @@
 
 namespace stt {
 
-LinesRenderer* LinesRenderer::lines_renderer = nullptr;
+LinesRenderer* LinesRenderer::lines_renderer_ = nullptr;
 
 void LinesRenderer::highlight(const LineSegments& lines,
                               const gui::Painter::Color& color)
@@ -30,9 +30,9 @@ void LinesRenderer::drawObjects(gui::Painter& painter)
 void highlightSteinerTree(const Tree& tree, gui::Gui* gui)
 {
   if (gui::Gui::enabled()) {
-    if (LinesRenderer::lines_renderer == nullptr) {
-      LinesRenderer::lines_renderer = new LinesRenderer();
-      gui->registerRenderer(LinesRenderer::lines_renderer);
+    if (LinesRenderer::lines_renderer_ == nullptr) {
+      LinesRenderer::lines_renderer_ = new LinesRenderer();
+      gui->registerRenderer(LinesRenderer::lines_renderer_);
     }
     LinesRenderer::LineSegments lines;
     for (int i = 0; i < tree.branchCount(); i++) {
@@ -44,7 +44,7 @@ void highlightSteinerTree(const Tree& tree, gui::Gui* gui)
       const int y2 = neighbor.y;
       lines.emplace_back(odb::Point(x1, y1), odb::Point(x2, y2));
     }
-    LinesRenderer::lines_renderer->highlight(lines, gui::Painter::kRed);
+    LinesRenderer::lines_renderer_->highlight(lines, gui::Painter::kRed);
   }
 }
 
diff --git a/src/stt/src/LinesRenderer.h b/src/stt/src/LinesRenderer.h
index c916454e6a1..292a0793bc3 100644
--- a/src/stt/src/LinesRenderer.h
+++ b/src/stt/src/LinesRenderer.h
@@ -23,7 +23,7 @@ class LinesRenderer : public gui::Renderer
   void highlight(const LineSegments& lines, const gui::Painter::Color& color);
   void drawObjects(gui::Painter& /* painter */) override;
   // singleton for debug functions
-  static LinesRenderer* lines_renderer;
+  static LinesRenderer* lines_renderer_;
 
  private:
   LineSegments lines_;
diff --git a/src/stt/src/SteinerTreeBuilder.cpp b/src/stt/src/SteinerTreeBuilder.cpp
index 9e5428168bf..06a6c84d584 100644
--- a/src/stt/src/SteinerTreeBuilder.cpp
+++ b/src/stt/src/SteinerTreeBuilder.cpp
@@ -79,7 +79,7 @@ Tree SteinerTreeBuilder::makeSteinerTree(const std::vector<int>& x,
     }
     // Fall back to flute if PD fails.
   }
-  return flute_->flute(x, y, flute_accuracy);
+  return flute_->flute(x, y, kFluteAccuracy);
 }
 
 Tree SteinerTreeBuilder::makeSteinerTree(const std::vector<int>& x,
diff --git a/src/stt/src/flt/flute.cpp b/src/stt/src/flt/flute.cpp
index e06eed412c1..b2d0219573b 100644
--- a/src/stt/src/flt/flute.cpp
+++ b/src/stt/src/flt/flute.cpp
@@ -134,9 +134,9 @@ static const char* readDecimalInt(const char* s, int& value)
   if (negative || *s == '+') {
     ++s;
   }
-  constexpr int zero_code = int('0');
+  constexpr int kZeroCode = int('0');
   while (*s >= '0' && *s <= '9') {
-    value = 10 * value + (int(*s) - zero_code);
+    value = 10 * value + (int(*s) - kZeroCode);
     ++s;
   }
   if (negative) {
@@ -445,15 +445,15 @@ int Flute::flutes_wl_medium_degree(int d,
   const int ub = d - 1 - lb;
 
   // Compute scores
-  constexpr double AAWL = 0.6;
-  constexpr double BBWL = 0.3;
-  const float CCWL = 7.4 / ((d + 10.) * (d - 3.));
-  const float DDWL = 4.8 / (d - 1);
+  constexpr double kAawl = 0.6;
+  constexpr double kBbwl = 0.3;
+  const float ccwl = 7.4 / ((d + 10.) * (d - 3.));
+  const float ddwl = 4.8 / (d - 1);
 
   // Compute penalty[]
   std::vector<float> penalty(degree);
-  const float dx = CCWL * (xs[d - 2] - xs[1]);
-  const float dy = CCWL * (ys[d - 2] - ys[1]);
+  const float dx = ccwl * (xs[d - 2] - xs[1]);
+  const float dy = ccwl * (ys[d - 2] - ys[1]);
   float pnlty = 0;
   for (int r = d / 2; r >= 0; r--, pnlty += dx) {
     penalty[r] = pnlty;
@@ -529,19 +529,19 @@ int Flute::flutes_wl_medium_degree(int d,
   for (int r = lb; r <= ub; r++) {
     if (si[r] == 0 || si[r] == d - 1) {
       score[nbp] = (xs[r + 1] - xs[r - 1]) - penalty[r]
-                   - AAWL * (ys[d - 2] - ys[1]) - DDWL * disty[r];
+                   - kAawl * (ys[d - 2] - ys[1]) - ddwl * disty[r];
     } else {
       score[nbp] = (xs[r + 1] - xs[r - 1]) - penalty[r]
-                   - BBWL * (ys[si[r] + 1] - ys[si[r] - 1]) - DDWL * disty[r];
+                   - kBbwl * (ys[si[r] + 1] - ys[si[r] - 1]) - ddwl * disty[r];
     }
     nbp++;
 
     if (s[r] == 0 || s[r] == d - 1) {
       score[nbp] = (ys[r + 1] - ys[r - 1]) - penalty[s[r]]
-                   - AAWL * (xs[d - 2] - xs[1]) - DDWL * distx[r];
+                   - kAawl * (xs[d - 2] - xs[1]) - ddwl * distx[r];
     } else {
       score[nbp] = (ys[r + 1] - ys[r - 1]) - penalty[s[r]]
-                   - BBWL * (xs[s[r] + 1] - xs[s[r] - 1]) - DDWL * distx[r];
+                   - kBbwl * (xs[s[r] + 1] - xs[s[r] - 1]) - ddwl * distx[r];
     }
     nbp++;
   }
@@ -991,15 +991,15 @@ Tree Flute::flutes_medium_degree(const int d,
   const int ub = d - 1 - lb;
 
   // Compute scores
-  constexpr double AA = 0.6;  // 2.0*BB
-  constexpr double BB = 0.3;
+  constexpr double kAa = 0.6;  // 2.0*BB
+  constexpr double kBb = 0.3;
 
-  const float CC = 7.4 / ((d + 10.) * (d - 3.));
-  const float DD = 4.8 / (d - 1);
+  const float cc = 7.4 / ((d + 10.) * (d - 3.));
+  const float dd = 4.8 / (d - 1);
 
   // Compute penalty[]
-  const float dx = CC * (xs[d - 2] - xs[1]);
-  const float dy = CC * (ys[d - 2] - ys[1]);
+  const float dx = cc * (xs[d - 2] - xs[1]);
+  const float dy = cc * (ys[d - 2] - ys[1]);
   float pnlty = 0;
   for (int r = d / 2; r >= 2; r--, pnlty += dx) {
     penalty[r] = pnlty, penalty[d - 1 - r] = pnlty;
@@ -1057,26 +1057,26 @@ Tree Flute::flutes_medium_degree(const int d,
   int nbp = 0;
   for (int r = lb; r <= ub; r++) {
     if (si[r] <= 1) {
-      score[nbp] = (xs[r + 1] - xs[r - 1]) - penalty[r] - AA * (ys[2] - ys[1])
-                   - DD * disty[r];
+      score[nbp] = (xs[r + 1] - xs[r - 1]) - penalty[r] - kAa * (ys[2] - ys[1])
+                   - dd * disty[r];
     } else if (si[r] >= d - 2) {
       score[nbp] = (xs[r + 1] - xs[r - 1]) - penalty[r]
-                   - AA * (ys[d - 2] - ys[d - 3]) - DD * disty[r];
+                   - kAa * (ys[d - 2] - ys[d - 3]) - dd * disty[r];
     } else {
       score[nbp] = (xs[r + 1] - xs[r - 1]) - penalty[r]
-                   - BB * (ys[si[r] + 1] - ys[si[r] - 1]) - DD * disty[r];
+                   - kBb * (ys[si[r] + 1] - ys[si[r] - 1]) - dd * disty[r];
     }
     nbp++;
 
     if (s[r] <= 1) {
       score[nbp] = (ys[r + 1] - ys[r - 1]) - penalty[s[r]]
-                   - AA * (xs[2] - xs[1]) - DD * distx[r];
+                   - kAa * (xs[2] - xs[1]) - dd * distx[r];
     } else if (s[r] >= d - 2) {
       score[nbp] = (ys[r + 1] - ys[r - 1]) - penalty[s[r]]
-                   - AA * (xs[d - 2] - xs[d - 3]) - DD * distx[r];
+                   - kAa * (xs[d - 2] - xs[d - 3]) - dd * distx[r];
     } else {
       score[nbp] = (ys[r + 1] - ys[r - 1]) - penalty[s[r]]
-                   - BB * (xs[s[r] + 1] - xs[s[r] - 1]) - DD * distx[r];
+                   - kBb * (xs[s[r] + 1] - xs[s[r] - 1]) - dd * distx[r];
     }
     nbp++;
   }