Added initial version of parallel for loop example

examples/CMakeLists.txt

@@ -57,6 +57,7 @@ add_example(multithreaded_object_ex)
 add_example(object_detector_advanced_ex)
 add_example(object_detector_ex)
 add_example(optimization_ex)
+add_example(parallel_for_ex)
 add_example(pipe_ex)
 add_example(pipe_ex_2)
 add_example(quantum_computing_ex)

examples/parallel_for_ex.cpp

+// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
+/*
+
+    This is an example illustrating the use of the parallel for loop
+    tools from the dlib C++ Library.
+
+
+*/
+
+
+#include <dlib/threads.h>
+#include <dlib/misc_api.h>  // for dlib::sleep
+#include <vector>
+#include <iostream>
+
+using namespace dlib;
+using namespace std;
+
+struct function_object
+{
+    function_object( std::vector<int>& vect ) : vect1(vect) {}
+
+    std::vector<int>& vect1;
+
+    void operator() (long i) const
+    {
+        vect1[i] = i;
+        dlib::sleep(100);
+    }
+};
+
+int main()
+{
+
+    const unsigned long num_threads = 4;
+    
+    std::vector<int> vect1(10);
+    parallel_for(num_threads, 0, vect1.size(), function_object(vect1));
+
+    for (unsigned long i = 0; i < vect1.size(); ++i)
+        cout << vect1[i] << endl;
+    cout << "\n**************************************\n";
+
+    vect1.assign(10, -1);
+    parallel_for(num_threads, 1, 5, function_object(vect1));
+    for (unsigned long i = 0; i < vect1.size(); ++i)
+        cout << vect1[i] << endl;
+    cout << "\n**************************************\n";
+
+
+// uncomment this line if your compiler supports the new C++0x lambda functions
+#define COMPILER_SUPPORTS_CPP0X_LAMBDA_FUNCTIONS
+#ifdef COMPILER_SUPPORTS_CPP0X_LAMBDA_FUNCTIONS
+
+    std::vector<int> vect2(10);
+    parallel_for(num_threads, 0, vect2.size(), [&](long i){
+        vect2[i] = i;
+        dlib::sleep(100);
+    });
+
+    for (unsigned long i = 0; i < vect2.size(); ++i)
+        cout << vect2[i] << endl;
+
+#endif
+
+}
+
+
+
+
+