From 42be860f735a96616a257684c97adc0b175cd95d Mon Sep 17 00:00:00 2001
From: Frank Dellaert <dellaert@gmail.com>
Date: Sat, 4 Feb 2023 10:35:42 -0800
Subject: [PATCH] Use c++17 in examples

---
 examples/ISAM2Example_SmartFactor.cpp    | 5 ++---
 examples/Pose3Localization.cpp           | 4 ++--
 examples/SFMExampleExpressions_bal.cpp   | 4 +---
 examples/SFMExample_bal.cpp              | 4 +---
 examples/SFMExample_bal_COLAMD_METIS.cpp | 4 +---
 examples/SolverComparer.cpp              | 6 +++---
 6 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/examples/ISAM2Example_SmartFactor.cpp b/examples/ISAM2Example_SmartFactor.cpp
index a874efc9a..51503e34e 100644
--- a/examples/ISAM2Example_SmartFactor.cpp
+++ b/examples/ISAM2Example_SmartFactor.cpp
@@ -87,9 +87,8 @@ int main(int argc, char* argv[]) {
     result.print();
 
     cout << "Detailed results:" << endl;
-    for (auto keyedStatus : result.detail->variableStatus) {
-      const auto& status = keyedStatus.second;
-      PrintKey(keyedStatus.first);
+    for (auto& [key, status] : result.detail->variableStatus) {
+      PrintKey(key);
       cout << " {" << endl;
       cout << "reeliminated: " << status.isReeliminated << endl;
       cout << "relinearized above thresh: " << status.isAboveRelinThreshold
diff --git a/examples/Pose3Localization.cpp b/examples/Pose3Localization.cpp
index 4fb200faf..e23e6902a 100644
--- a/examples/Pose3Localization.cpp
+++ b/examples/Pose3Localization.cpp
@@ -74,8 +74,8 @@ int main(const int argc, const char* argv[]) {
 
   // Calculate and print marginal covariances for all variables
   Marginals marginals(*graph, result);
-  for (const auto& key_pose : result.extract<Pose3>()) {
-    std::cout << marginals.marginalCovariance(key_pose.first) << endl;
+  for (const auto& [key, pose] : result.extract<Pose3>()) {
+    std::cout << marginals.marginalCovariance(key) << endl;
   }
   return 0;
 }
diff --git a/examples/SFMExampleExpressions_bal.cpp b/examples/SFMExampleExpressions_bal.cpp
index 8a5a12e56..edd46b5e2 100644
--- a/examples/SFMExampleExpressions_bal.cpp
+++ b/examples/SFMExampleExpressions_bal.cpp
@@ -79,9 +79,7 @@ int main(int argc, char* argv[]) {
   for (const SfmTrack& track : mydata.tracks) {
     // Leaf expression for j^th point
     Point3_ point_('p', j);
-    for (const SfmMeasurement& m : track.measurements) {
-      size_t i = m.first;
-      Point2 uv = m.second;
+    for (const auto& [i, uv] : track.measurements) {
       // Leaf expression for i^th camera
       Expression<SfmCamera> camera_(C(i));
       // Below an expression for the prediction of the measurement:
diff --git a/examples/SFMExample_bal.cpp b/examples/SFMExample_bal.cpp
index 10563760d..3edf1f89b 100644
--- a/examples/SFMExample_bal.cpp
+++ b/examples/SFMExample_bal.cpp
@@ -57,9 +57,7 @@ int main (int argc, char* argv[]) {
   // Add measurements to the factor graph
   size_t j = 0;
   for(const SfmTrack& track: mydata.tracks) {
-    for(const SfmMeasurement& m: track.measurements) {
-      size_t i = m.first;
-      Point2 uv = m.second;
+    for (const auto& [i, uv] : track.measurements) {
       graph.emplace_shared<MyFactor>(uv, noise, C(i), P(j)); // note use of shorthand symbols C and P
     }
     j += 1;
diff --git a/examples/SFMExample_bal_COLAMD_METIS.cpp b/examples/SFMExample_bal_COLAMD_METIS.cpp
index 92d779a56..5134285c7 100644
--- a/examples/SFMExample_bal_COLAMD_METIS.cpp
+++ b/examples/SFMExample_bal_COLAMD_METIS.cpp
@@ -59,9 +59,7 @@ int main(int argc, char* argv[]) {
   // Add measurements to the factor graph
   size_t j = 0;
   for (const SfmTrack& track : mydata.tracks) {
-    for (const SfmMeasurement& m : track.measurements) {
-      size_t i = m.first;
-      Point2 uv = m.second;
+    for (const auto& [i, uv] : track.measurements) {
       graph.emplace_shared<MyFactor>(
           uv, noise, C(i), P(j));  // note use of shorthand symbols C and P
     }
diff --git a/examples/SolverComparer.cpp b/examples/SolverComparer.cpp
index 34b30c10a..7e451ca99 100644
--- a/examples/SolverComparer.cpp
+++ b/examples/SolverComparer.cpp
@@ -557,12 +557,12 @@ void runPerturb()
 
   // Perturb values
   VectorValues noise;
-  for(const auto& key_dim: initial.dims())
+  for(const auto& [key, dim]: initial.dims())
   {
-    Vector noisev(key_dim.second);
+    Vector noisev(dim);
     for(Vector::Index i = 0; i < noisev.size(); ++i)
       noisev(i) = normal(rng);
-    noise.insert(key_dim.first, noisev);
+    noise.insert(key, noisev);
   }
   Values perturbed = initial.retract(noise);