diff --git a/src/cts/src/Clock.cpp b/src/cts/src/Clock.cpp
index c0cf60495b..84b602c84a 100644
--- a/src/cts/src/Clock.cpp
+++ b/src/cts/src/Clock.cpp
@@ -106,7 +106,7 @@ Box<int> Clock::computeSinkRegion()
 }
 
 Box<double> Clock::computeSinkRegionClustered(
-    std::vector<std::pair<float, float>> sinks)
+    const std::vector<std::pair<float, float>>& sinks)
 {
   auto xMin = std::numeric_limits<float>::max();
   auto xMax = std::numeric_limits<float>::lowest();
diff --git a/src/cts/src/Clock.h b/src/cts/src/Clock.h
index 5b3abf13ed..8ce130c257 100644
--- a/src/cts/src/Clock.h
+++ b/src/cts/src/Clock.h
@@ -248,7 +248,7 @@ class Clock
 
   Box<int> computeSinkRegion();
   Box<double> computeSinkRegionClustered(
-      std::vector<std::pair<float, float>> sinks);
+      const std::vector<std::pair<float, float>>& sinks);
   Box<double> computeNormalizedSinkRegion(double factor);
 
   void report(utl::Logger* logger) const;
diff --git a/src/cts/src/Clustering.cpp b/src/cts/src/Clustering.cpp
index f8a66bf13c..4e0f77a444 100644
--- a/src/cts/src/Clustering.cpp
+++ b/src/cts/src/Clustering.cpp
@@ -66,11 +66,13 @@ using utl::CTS;
 struct Sink
 {
   Sink(const float x, const float y, const unsigned idx)
-      : x(x), y(y), cluster_idx(-1), sink_idx(idx){};
+      : x(x), y(y), sink_idx(idx)
+  {
+  }
 
   // location
   const float x, y;
-  int cluster_idx;
+  int cluster_idx{-1};
   const unsigned sink_idx;  // index in sinks_
 };
 
diff --git a/src/cts/src/HTreeBuilder.cpp b/src/cts/src/HTreeBuilder.cpp
index a560067e83..86998e098f 100644
--- a/src/cts/src/HTreeBuilder.cpp
+++ b/src/cts/src/HTreeBuilder.cpp
@@ -64,8 +64,8 @@ void HTreeBuilder::preSinkClustering(
                                        (float) inst.getY() / wireSegmentUnit_);
       mapLocationToSink_[normLocation] = &inst;
       if (!fuzzyEqual(inst.getInsertionDelay(), 0.0, 1e-6)) {
-        setSinkInsertionDelay(
-            normLocation, (double) inst.getInsertionDelay() / wireSegmentUnit_);
+        setSinkInsertionDelay(normLocation,
+                              inst.getInsertionDelay() / wireSegmentUnit_);
         // clang-format off
 	debugPrint(logger_, CTS, "clustering", 1, "sink {} has insDelay {} at {}",
 		   inst.getName(), getSinkInsertionDelay(normLocation),
@@ -358,7 +358,7 @@ void plotBlockage(std::ofstream& file, odb::dbDatabase* db_, int scalingFactor)
     int h = bbox->yMax() / scalingFactor - bbox->yMin() / scalingFactor;
     file << i++ << " " << x << " " << y << " " << w << " " << h
          << " block  scalingFactor=";
-    file << scalingFactor << " " << blockage->getId() << std::endl;
+    file << scalingFactor << " " << blockage->getId() << '\n';
   }
 }
 
@@ -385,7 +385,7 @@ void plotSinks(std::ofstream& file, const std::vector<Point<double>>& sinks)
     double h = 1;
     auto name = "sink_";
     file << cnt++ << " " << x << " " << y << " " << w << " " << h;
-    file << " " << name << " " << std::endl;
+    file << " " << name << '\n';
   }
 }
 
@@ -1252,7 +1252,7 @@ std::string HTreeBuilder::plotHTree()
           double y2 = branchPoint.getY();
           std::string name = "buffer";
           file << levelIdx << " " << x1 << " " << y1 << " " << x2 << " " << y2;
-          file << " " << name << std::endl;
+          file << " " << name << '\n';
         });
   }
 
@@ -1271,7 +1271,7 @@ std::string HTreeBuilder::plotHTree()
 
           file << numSinks << " " << loc.getX() << " " << loc.getY();
           file << " " << px << " " << py << " leafbuffer " << name2;
-          file << " z=" << wireSegmentUnit_ << std::endl;
+          file << " z=" << wireSegmentUnit_ << '\n';
           ++numSinks;
         }
       });
diff --git a/src/cts/src/HTreeBuilder.h b/src/cts/src/HTreeBuilder.h
index 0b8851d700..c6980f3fe0 100644
--- a/src/cts/src/HTreeBuilder.h
+++ b/src/cts/src/HTreeBuilder.h
@@ -89,7 +89,7 @@ class HTreeBuilder : public TreeBuilder
    public:
     static constexpr unsigned NO_PARENT = std::numeric_limits<unsigned>::max();
 
-    explicit LevelTopology(double length) : length_(length){};
+    explicit LevelTopology(double length) : length_(length) {}
 
     void addWireSegment(unsigned idx) { wireSegments_.push_back(idx); }
 
diff --git a/src/cts/src/LevelBalancer.cpp b/src/cts/src/LevelBalancer.cpp
index 718b333a65..d17dfd1991 100644
--- a/src/cts/src/LevelBalancer.cpp
+++ b/src/cts/src/LevelBalancer.cpp
@@ -83,7 +83,7 @@ unsigned LevelBalancer::computeMaxTreeDepth(TreeBuilder* parent)
 }
 
 void LevelBalancer::addBufferLevels(TreeBuilder* builder,
-                                    const std::vector<ClockInst*> cluster,
+                                    const std::vector<ClockInst*>& cluster,
                                     ClockSubNet* driverNet,
                                     const unsigned bufLevels,
                                     const std::string& nameSuffix)
diff --git a/src/cts/src/LevelBalancer.h b/src/cts/src/LevelBalancer.h
index ee614f0e73..cd774bf11a 100644
--- a/src/cts/src/LevelBalancer.h
+++ b/src/cts/src/LevelBalancer.h
@@ -98,7 +98,7 @@ class LevelBalancer
 
   void run();
   void addBufferLevels(TreeBuilder* builder,
-                       std::vector<ClockInst*> cluster,
+                       const std::vector<ClockInst*>& cluster,
                        ClockSubNet* driverNet,
                        unsigned bufLevels,
                        const std::string& nameSuffix);
diff --git a/src/cts/src/SinkClustering.cpp b/src/cts/src/SinkClustering.cpp
index ceeefe5f52..d8d2eedab7 100644
--- a/src/cts/src/SinkClustering.cpp
+++ b/src/cts/src/SinkClustering.cpp
@@ -40,6 +40,7 @@
 #include <fstream>
 #include <iostream>
 #include <map>
+#include <sstream>
 #include <string>
 #include <tuple>
 #include <vector>
@@ -307,9 +308,9 @@ bool SinkClustering::findBestMatching(const unsigned groupSize)
         // Add vectors in case they are no allocated yet. (Depends if a new
         // cluster was defined above)
         if (solutions[j].size() < (clusters[j] + 1)) {
-          solutions[j].push_back({});
-          solutionPoints[j].push_back({});
-          solutionPointsIdx[j].push_back({});
+          solutions[j].emplace_back();
+          solutionPoints[j].emplace_back();
+          solutionPointsIdx[j].emplace_back();
         }
         // Save the current Point in it's respective cluster. (Depends if a new
         // cluster was defined above)
@@ -326,9 +327,9 @@ bool SinkClustering::findBestMatching(const unsigned groupSize)
     // one late).
     for (unsigned j = (i + 1); j < groupSize; ++j) {
       if (solutions[j].size() < (clusters[j] + 1)) {
-        solutions[j].push_back({});
-        solutionPoints[j].push_back({});
-        solutionPointsIdx[j].push_back({});
+        solutions[j].emplace_back();
+        solutionPoints[j].emplace_back();
+        solutionPointsIdx[j].emplace_back();
       }
       // Thus here we will assign the Points missing from those solutions.
       const unsigned idx = thetaIndexVector_[i].second;
@@ -372,9 +373,9 @@ bool SinkClustering::findBestMatching(const unsigned groupSize)
         }
       }
       if (solutions[j].size() < (clusters[j] + 1)) {
-        solutions[j].push_back({});
-        solutionPoints[j].push_back({});
-        solutionPointsIdx[j].push_back({});
+        solutions[j].emplace_back();
+        solutionPoints[j].emplace_back();
+        solutionPointsIdx[j].emplace_back();
       }
       solutionPoints[j][clusters[j]].push_back(p);
       solutionPointsIdx[j][clusters[j]].push_back(idx);
@@ -417,11 +418,12 @@ bool SinkClustering::findBestMatching(const unsigned groupSize)
   if (logger_->debugCheck(CTS, "clustering", 2)) {
     size_t solnIndex = 0;
     for (const std::vector<unsigned>& soln : bestSolution_) {
-      std::cout << "Solution " << solnIndex << "[" << soln.size() << "]: ";
+      std::ostringstream s;
+      s << "Solution " << solnIndex << "[" << soln.size() << "]: ";
       for (const unsigned i : soln) {
-        std::cout << i << " ";
+        s << i << " ";
       }
-      std::cout << std::endl;
+      logger_->debug(CTS, "clustering", "{}", s.str());
       ++solnIndex;
     }
   }
diff --git a/src/cts/src/TechChar.cpp b/src/cts/src/TechChar.cpp
index f70ffa2fff..31488ba127 100644
--- a/src/cts/src/TechChar.cpp
+++ b/src/cts/src/TechChar.cpp
@@ -480,32 +480,34 @@ void TechChar::initCharacterization()
   float maxBuffCap = 0.0;
   std::string bufMasterName;
   std::vector<float> axisSlews, axisLoads;
-  for (int i = 0; i < masterVector.size(); i++) {
+  for (const std::string& master_name : masterVector) {
     float maxCap = 0.0;
     bool maxCapExist = false;
-    odb::dbMaster* buf = db_->findMaster(masterVector[i].c_str());
+    odb::dbMaster* buf = db_->findMaster(master_name.c_str());
     sta::Cell* masterCell = db_network_->dbToSta(buf);
     sta::LibertyCell* libertyCell = db_network_->libertyCell(masterCell);
     sta::LibertyPort *input, *output;
     libertyCell->bufferPorts(input, output);
     output->capacitanceLimit(sta::MinMax::max(), maxCap, maxCapExist);
     sta::LibertyLibrary* lib = libertyCell->libertyLibrary();
-    if (!maxCapExist)
+    if (!maxCapExist) {
       lib->defaultMaxCapacitance(maxCap, maxCapExist);
-    if (!maxCapExist)
+    }
+    if (!maxCapExist) {
       logger_->error(
-          CTS, 111, "No max capacitance found for cell {}.", masterVector[i]);
+          CTS, 111, "No max capacitance found for cell {}.", master_name);
+    }
     if (maxCap >= maxBuffCap) {
       maxBuffCap = maxCap;
       charBuf_ = buf;
-      bufMasterName = masterVector[i];
+      bufMasterName = master_name;
     }
     // collect slews and caps from NLDM table axis from all buffers in list
     collectSlewsLoadsFromTableAxis(
         libertyCell, input, output, axisSlews, axisLoads);
   }
 
-  if (bufMasterName == "") {
+  if (bufMasterName.empty()) {
     logger_->error(
         CTS,
         113,
@@ -573,7 +575,7 @@ void TechChar::initCharacterization()
     wirelengthsToTest_.push_back(wirelengthInter);
   }
 
-  if (wirelengthsToTest_.size() < 1) {
+  if (wirelengthsToTest_.empty()) {
     logger_->error(
         CTS,
         75,
@@ -608,16 +610,19 @@ void TechChar::initCharacterization()
       if (!maxSlewExist) {
         lib->defaultMaxSlew(maxSlew, maxSlewExist);
       }
-      if (!maxSlewExist)
+      if (!maxSlewExist) {
         logger_->error(
             CTS, 107, "No max slew found for cell {}.", bufMasterName);
+      }
 
       output->capacitanceLimit(sta::MinMax::max(), maxCap, maxCapExist);
-      if (!maxCapExist)
+      if (!maxCapExist) {
         lib->defaultMaxCapacitance(maxCap, maxCapExist);
-      if (!maxCapExist)
+      }
+      if (!maxCapExist) {
         logger_->error(
             CTS, 108, "No max capacitance found for cell {}.", bufMasterName);
+      }
       options_->setMaxCharSlew(maxSlew);
       options_->setMaxCharCap(maxCap);
     }
@@ -812,13 +817,13 @@ void TechChar::collectSlewsLoadsFromTableAxis(sta::LibertyCell* libCell,
         }
       }
       if (slews) {
-        for (size_t i = 0; i < slews->size(); ++i) {
-          axisSlews.push_back((*slews)[i]);
+        for (const float slew : *slews) {
+          axisSlews.push_back(slew);
         }
       }
       if (loads) {
-        for (size_t i = 0; i < loads->size(); ++i) {
-          axisLoads.push_back((*loads)[i]);
+        for (const float load : *loads) {
+          axisLoads.push_back(load);
         }
       }
     }
@@ -960,18 +965,19 @@ std::vector<TechChar::SolutionData> TechChar::createPatterns(
        solutionCounterInt++) {
     // Creates a bitset that represents the buffer locations.
     const std::bitset<5> solutionCounter(solutionCounterInt);
-    unsigned short int wireCounter = 0;
+    int wireCounter = 0;
     SolutionData topology;
     // Creates the starting net.
-    const std::string netName = "net_" + std::to_string(setupWirelength) + "_"
-                                + solutionCounter.to_string() + "_"
-                                + std::to_string(wireCounter);
+    const std::string netName = fmt::format("net_{}_{}_{}",
+                                            setupWirelength,
+                                            solutionCounter.to_string(),
+                                            wireCounter);
     net = odb::dbNet::create(charBlock_, netName.c_str());
     odb::dbWire::create(net);
     net->setSigType(odb::dbSigType::SIGNAL);
     // Creates the input port.
     const std::string inPortName
-        = "in_" + std::to_string(setupWirelength) + solutionCounter.to_string();
+        = fmt::format("in_{}{}", setupWirelength, solutionCounter.to_string());
     odb::dbBTerm* inPort = odb::dbBTerm::create(
         net, inPortName.c_str());  // sig type is signal by default
     inPort->setIoType(odb::dbIoType::INPUT);
@@ -993,9 +999,10 @@ std::vector<TechChar::SolutionData> TechChar::createPatterns(
         // Buffer, need to create the instance and a new net.
         nodesWithoutBuf++;
         // Creates a new buffer instance.
-        const std::string bufName = "buf_" + std::to_string(setupWirelength)
-                                    + "_" + solutionCounter.to_string() + "_"
-                                    + std::to_string(wireCounter);
+        const std::string bufName = fmt::format("buf_{}_{}_{}",
+                                                setupWirelength,
+                                                solutionCounter.to_string(),
+                                                wireCounter);
         // clang-format off
         debugPrint(logger_, CTS, "tech char", 1, "  buffer {} at node:{} "
                    "topo:{}", bufName, nodeIndex, solutionCounterInt);
@@ -1011,9 +1018,10 @@ std::vector<TechChar::SolutionData> TechChar::createPatterns(
         topology.nodesWithoutBufVector.push_back(nodesWithoutBuf);
         // Creates a new net.
         wireCounter++;
-        const std::string netName = "net_" + std::to_string(setupWirelength)
-                                    + "_" + solutionCounter.to_string() + "_"
-                                    + std::to_string(wireCounter);
+        const std::string netName = fmt::format("net_{}_{}_{}",
+                                                setupWirelength,
+                                                solutionCounter.to_string(),
+                                                wireCounter);
         net = odb::dbNet::create(charBlock_, netName.c_str());
         odb::dbWire::create(net);
         bufInstanceOutPin->connect(net);
@@ -1034,8 +1042,8 @@ std::vector<TechChar::SolutionData> TechChar::createPatterns(
       }
     }
     // Finishing up the topology with the output port.
-    const std::string outPortName = "out_" + std::to_string(setupWirelength)
-                                    + solutionCounter.to_string();
+    const std::string outPortName
+        = fmt::format("out_{}{}", setupWirelength, solutionCounter.to_string());
     odb::dbBTerm* outPort = odb::dbBTerm::create(
         net, outPortName.c_str());  // sig type is signal by default
     outPort->setIoType(odb::dbIoType::OUTPUT);
@@ -1454,7 +1462,7 @@ std::vector<TechChar::ResultData> TechChar::characterizationPostProcess()
   // select only 3 of them.
   for (auto& keyResults : solutionMap_) {
     std::vector<ResultData> resultVector = keyResults.second;
-    for (ResultData selectedResults : resultVector) {
+    for (const ResultData& selectedResults : resultVector) {
       selectedSolutions.push_back(selectedResults);
     }
   }
@@ -1506,8 +1514,8 @@ std::vector<TechChar::ResultData> TechChar::characterizationPostProcess()
         if (std::find(masterNames_.begin(), masterNames_.end(), topologyS)
             == masterNames_.end()) {
           // Is a number (i.e. a wire segment).
-          topologyResult.push_back(std::to_string(
-              std::stod(topologyS) / static_cast<float>(solution.wirelength)));
+          topologyResult.push_back(
+              std::to_string(std::stod(topologyS) / solution.wirelength));
         } else {
           topologyResult.push_back(topologyS);
         }
@@ -1559,7 +1567,7 @@ void TechChar::create()
   }
   // Setup of the attributes required to run the characterization.
   initCharacterization();
-  long unsigned int topologiesCreated = 0;
+  int64_t topologiesCreated = 0;
   for (unsigned setupWirelength : wirelengthsToTest_) {
     // Creates the topologies for the current wirelength.
     std::vector<SolutionData> topologiesVector
@@ -1738,7 +1746,7 @@ unsigned TechChar::getBufferingCombo(size_t numBuffers, size_t numNodes)
   auto iter = bufferingComboTable_.find(iPair);
   if (iter != bufferingComboTable_.end()) {
     if (logger_->debugCheck(CTS, "tech char", 1)) {
-      tmp << "Monotonic entries (hashed): " << iter->second << std::endl;
+      tmp << "Monotonic entries (hashed): " << iter->second << '\n';
       logger_->report(tmp.str());
     }
     return iter->second;
diff --git a/src/cts/src/TritonCTS.cpp b/src/cts/src/TritonCTS.cpp
index 7d4bda3bb9..0f8680460f 100644
--- a/src/cts/src/TritonCTS.cpp
+++ b/src/cts/src/TritonCTS.cpp
@@ -940,7 +940,7 @@ void TritonCTS::populateTritonCTS()
       // Since a set is unique, only the nets not found by dbSta are added.
       clockNets.insert(net);
     }
-    clockNetsInfo.emplace_back(std::make_pair(clockNets, std::string("")));
+    clockNetsInfo.emplace_back(clockNets, "");
   } else {
     std::set<odb::dbNet*> allClkNets;
     staClockNets_ = openSta_->findClkNets();
@@ -955,7 +955,7 @@ void TritonCTS::populateTritonCTS()
               CTS, 114, "Clock {} overlaps a previous clock.", clkName);
         }
       }
-      clockNetsInfo.emplace_back(std::make_pair(clkNets, clkName));
+      clockNetsInfo.emplace_back(clkNets, clkName);
       allClkNets.insert(clkNets.begin(), clkNets.end());
     }
   }