diff --git a/Principal_component_analysis/examples/Principal_component_analysis/linear_least_squares_fitting_tetrahedra_3.cpp b/Principal_component_analysis/examples/Principal_component_analysis/linear_least_squares_fitting_tetrahedra_3.cpp
index c91305d713e..aed293b514d 100644
--- a/Principal_component_analysis/examples/Principal_component_analysis/linear_least_squares_fitting_tetrahedra_3.cpp
+++ b/Principal_component_analysis/examples/Principal_component_analysis/linear_least_squares_fitting_tetrahedra_3.cpp
@@ -4,6 +4,7 @@
 #include <CGAL/Cartesian.h>
 #include <CGAL/linear_least_squares_fitting_3.h>
 #include <list>
+#include <cstdlib> // for std::rand
 
 typedef double               FT;
 typedef CGAL::Cartesian<FT>  K;
@@ -14,7 +15,7 @@ typedef K::Tetrahedron_3     Tetrahedron;
 
 FT random_value()
 {
-	return (FT)rand() / (FT)RAND_MAX;
+	return (FT)std::rand() / (FT)RAND_MAX;
 }
 
 Point random_point()
diff --git a/Principal_component_analysis/examples/Principal_component_analysis/linear_least_squares_fitting_triangles_3.cpp b/Principal_component_analysis/examples/Principal_component_analysis/linear_least_squares_fitting_triangles_3.cpp
index fab4923355b..0aca3916ef5 100644
--- a/Principal_component_analysis/examples/Principal_component_analysis/linear_least_squares_fitting_triangles_3.cpp
+++ b/Principal_component_analysis/examples/Principal_component_analysis/linear_least_squares_fitting_triangles_3.cpp
@@ -3,6 +3,7 @@
 #include <CGAL/Cartesian.h>
 #include <CGAL/linear_least_squares_fitting_3.h>
 #include <list>
+#include <cstdlib> // for std::rand
 
 typedef double               FT;
 typedef CGAL::Cartesian<FT>  K;
@@ -13,7 +14,7 @@ typedef K::Triangle_3        Triangle;
 
 FT random_value()
 {
-	return (FT)rand() / (FT)RAND_MAX;
+	return (FT)std::rand() / (FT)RAND_MAX;
 }
 
 Point random_point()
diff --git a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_points_2.cpp b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_points_2.cpp
index 87a2231726a..cb35a98a264 100644
--- a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_points_2.cpp
+++ b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_points_2.cpp
@@ -39,7 +39,7 @@ void test_2D()
   if(!line.is_horizontal())
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
@@ -82,7 +82,7 @@ void test_2D_point_set(const unsigned int nb_points)
   if(!line.is_horizontal())
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
diff --git a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_points_3.cpp b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_points_3.cpp
index 9d5b4f77b09..51bb1734f7a 100644
--- a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_points_3.cpp
+++ b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_points_3.cpp
@@ -71,14 +71,14 @@ void test_one_point()
   if(!parallel(horizontal_plane,plane))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
 Point random_point_xy()
 {
-  FT x = (FT)((double)rand() / (double)RAND_MAX);
-  FT y = (FT)((double)rand() / (double)RAND_MAX);
+  FT x = (FT)((double)std::rand() / (double)RAND_MAX);
+  FT y = (FT)((double)std::rand() / (double)RAND_MAX);
   return Point(x,y,0);
 }
 
@@ -102,7 +102,7 @@ void test_point_set(const unsigned int nb_points)
   if(!parallel(horizontal_plane,plane))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
diff --git a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_rectangles_2.cpp b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_rectangles_2.cpp
index 3bc7deb235b..722e65b3cd6 100644
--- a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_rectangles_2.cpp
+++ b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_rectangles_2.cpp
@@ -45,7 +45,7 @@ void test_1()
   if(!(line.is_horizontal() && std::abs(line.c()/line.b()- -2) <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
@@ -87,7 +87,7 @@ void test_2()
   if(!(std::abs(-1.0*line.a()/line.b() - -1.0*line1.a()/line1.b()) <= THRESHOLD && std::abs(line.c()/line.b() - line1.c()/line1.b()) <= THRESHOLD && std::abs(quality1 - quality) <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
@@ -128,7 +128,7 @@ void test_3()
   if(!(std::abs(-1.0*line.a()/line.b() - -1.0*line1.a()/line1.b()) <= THRESHOLD && std::abs(line.c()/line.b() - line1.c()/line1.b()) <= THRESHOLD && std::abs(quality1 - quality) <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
diff --git a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_segments_2.cpp b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_segments_2.cpp
index 9725b6d924d..336441996c6 100644
--- a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_segments_2.cpp
+++ b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_segments_2.cpp
@@ -42,7 +42,7 @@ void test_1()
   if(!(std::abs(-1.0*line.a()/line.b() - 1) <= THRESHOLD && std::abs(line.c()/line.b()) <= THRESHOLD && 1 - quality <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
@@ -69,7 +69,7 @@ void test_2()
   if(!(std::abs(-1.0*line.a()/line.b() - 1) <= THRESHOLD && std::abs(line.c()/line.b()) <= THRESHOLD && 1 - quality <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
@@ -98,7 +98,7 @@ void test_3()
   if(!(std::abs(-1.0*line.a()/line.b() - 1) <= THRESHOLD && std::abs(line.c()/line.b()) <= THRESHOLD && 1 - quality <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
@@ -140,7 +140,7 @@ void test_4()
   if(!(std::abs(-1.0*line.a()/line.b() - -1.0*line1.a()/line1.b()) <= THRESHOLD && std::abs(line.c()/line.b() - line1.c()/line1.b()) <= THRESHOLD && std::abs(quality1 - quality) <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
@@ -189,7 +189,7 @@ void test_5(const unsigned int nb_points)
   if(!(std::abs(-1.0*line.a()/line.b() - -1.0*line1.a()/line1.b()) <= THRESHOLD && std::abs(line.c()/line.b() - line1.c()/line1.b()) <= THRESHOLD && std::abs(quality1 - quality) <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 
 }
diff --git a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_triangles_2.cpp b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_triangles_2.cpp
index 63a594417a1..a3855c3f376 100644
--- a/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_triangles_2.cpp
+++ b/Principal_component_analysis/test/Principal_component_analysis/linear_least_squares_fitting_triangles_2.cpp
@@ -54,7 +54,7 @@ void test_1()
   if(!(std::abs(-1.0*line.a()/line.b() - -1.0*line1.a()/line1.b()) <= THRESHOLD && std::abs(line.c()/line.b() - line1.c()/line1.b()) <= THRESHOLD && std::abs(quality1 - quality) <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }
 
@@ -96,7 +96,7 @@ void test_2()
   if(!(std::abs(-1.0*line.a()/line.b() - -1.0*line1.a()/line1.b()) <= THRESHOLD && std::abs(line.c()/line.b() - line1.c()/line1.b()) <= THRESHOLD && std::abs(quality1 - quality) <= THRESHOLD))
   {
     std::cout << "failure" << std::endl;
-    exit(1); // failure
+    std::exit(1); // failure
   }
 }