diff --git a/CMakeLists.txt b/CMakeLists.txt
index feaa34f7..6a70444e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,6 +5,7 @@ project(Algorithms_in_C
     DESCRIPTION "Set of algorithms implemented in C."
 )
 
+# Set compilation standards
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_C_STANDARD_REQUIRED YES)
 
@@ -13,8 +14,12 @@ if(MSVC)
     # add_compile_options(/Za)
 endif(MSVC)
 
+# check for math library
+# addresses a bug when linking on OSX
 find_library(MATH_LIBRARY m)
 
+# Optional flag - can be set by user 
+# Default "ON"
 option(USE_OPENMP "flag to use OpenMP for multithreading" ON)
 if(USE_OPENMP)
     find_package(OpenMP)
@@ -25,6 +30,24 @@ if(USE_OPENMP)
     endif()
 endif()
 
+## Check for some required header files
+include(CheckIncludeFile)
+include(CheckSymbolExists)
+check_include_file(stdbool.h HAS_STDBOOL_H)
+check_include_file(inttypes.h HAS_INTTYPES_H)
+check_include_file(complex.h HAS_COMPLEX_H)
+if(HAS_COMPLEX_H)
+    check_symbol_exists(complex complex.h HAS_COMPLEX_TYPE)
+endif(HAS_COMPLEX_H)
+if (NOT HAS_STDBOOL_H)
+    message(FATAL_ERROR "Missing required header: 'stdbool.h'")
+endif()
+if (NOT HAS_INTTYPES_H)
+    message(FATAL_ERROR "Missing required header: 'inttypes.h'")
+endif()
+
+## Add subdirectories containing CMakeLists.txt 
+# to configure and compile files in the respective folders
 add_subdirectory(misc)
 add_subdirectory(sorting)
 add_subdirectory(graphics)
@@ -35,6 +58,7 @@ add_subdirectory(project_euler)
 add_subdirectory(machine_learning)
 add_subdirectory(numerical_methods)
 
+## Configure Doxygen documentation system
 cmake_policy(SET CMP0054 NEW)
 cmake_policy(SET CMP0057 NEW)
 find_package(Doxygen OPTIONAL_COMPONENTS dot dia)
@@ -77,7 +101,7 @@ if(DOXYGEN_FOUND)
     )
 endif()
 
-
+## Enable tool to generate binary distribution files
 set(CPACK_PROJECT_NAME ${PROJECT_NAME})
 set(CPACK_PROJECT_VERSION ${PROJECT_VERSION})
 include(CPack)
diff --git a/client_server/CMakeLists.txt b/client_server/CMakeLists.txt
index 70d08ad8..66a6b043 100644
--- a/client_server/CMakeLists.txt
+++ b/client_server/CMakeLists.txt
@@ -1,45 +1,44 @@
-# include(CheckIncludeFile)
-# check_include_file(arpa/inet.h ARPA_HEADERS)
-# if(NOT ARPA_HEADERS)
-#     check_include_file(winsock2.h WINSOCK_HEADER)
-#     if(NOT WINSOCK_HEADER)
-#         message(FATAL_ERROR "socket headers not found in system.")
-#     endif()
-# endif()
+if(WIN32)
+    check_include_file(winsock2.h WINSOCK_HEADER)
+else()
+    check_include_file(arpa/inet.h ARPA_HEADERS)
+endif()
 
-# check_include_file(unistd.h HAS_UNISTD)
+if(ARPA_HEADERS OR WINSOCK_HEADER)
+    # If necessary, use the RELATIVE flag, otherwise each source file may be listed
+    # with full pathname. RELATIVE may makes it easier to extract an executable name
+    # automatically.
+    file( GLOB APP_SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.c )
+    # file( GLOB APP_SOURCES ${CMAKE_SOURCE_DIR}/*.c )
+    # AUX_SOURCE_DIRECTORY(${CMAKE_CURRENT_SOURCE_DIR} APP_SOURCES)
+    foreach( testsourcefile ${APP_SOURCES} )
+        # I used a simple string replace, to cut off .cpp.
+        string( REPLACE ".c" "" testname ${testsourcefile} )
+        add_executable( ${testname} ${testsourcefile} )
+        
+        if(OpenMP_C_FOUND)
+            target_link_libraries(${testname} PRIVATE OpenMP::OpenMP_C)
+        endif()
+        if(MATH_LIBRARY)
+            target_link_libraries(${testname} PRIVATE ${MATH_LIBRARY})
+        endif()
+        
+        # if(HAS_UNISTD)
+        #     target_compile_definitions(${testname} PRIVATE HAS_UNISTD)
+        # endif()
+        # if(ARPA_HEADERS)
+        #     target_compile_definitions(${testname} PRIVATE ARPA_HEADERS)
+        # else()
+        #     target_compile_definitions(${testname} PRIVATE WINSOCK_HEADER)
+        # endif()
 
-# If necessary, use the RELATIVE flag, otherwise each source file may be listed
-# with full pathname. RELATIVE may makes it easier to extract an executable name
-# automatically.
-file( GLOB APP_SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.c )
-# file( GLOB APP_SOURCES ${CMAKE_SOURCE_DIR}/*.c )
-# AUX_SOURCE_DIRECTORY(${CMAKE_CURRENT_SOURCE_DIR} APP_SOURCES)
-foreach( testsourcefile ${APP_SOURCES} )
-    # I used a simple string replace, to cut off .cpp.
-    string( REPLACE ".c" "" testname ${testsourcefile} )
-    add_executable( ${testname} ${testsourcefile} )
-    
-    if(OpenMP_C_FOUND)
-        target_link_libraries(${testname} PRIVATE OpenMP::OpenMP_C)
-    endif()
-    if(MATH_LIBRARY)
-        target_link_libraries(${testname} PRIVATE ${MATH_LIBRARY})
-    endif()
-    
-    if(HAS_UNISTD)
-        target_compile_definitions(${testname} PRIVATE HAS_UNISTD)
-    endif()
-    # if(ARPA_HEADERS)
-    #     target_compile_definitions(${testname} PRIVATE ARPA_HEADERS)
-    # else()
-    #     target_compile_definitions(${testname} PRIVATE WINSOCK_HEADER)
-    # endif()
+        if(WINSOCK_HEADER)
+            target_link_libraries(${testname} PRIVATE ws2_32)   # link winsock library on windows
+        endif()
 
-    if(WIN32)
-        target_link_libraries(${testname} PRIVATE ws2_32)   # link winsock library on windows
-    endif()
+        install(TARGETS ${testname} DESTINATION "bin/client_server")
 
-    install(TARGETS ${testname} DESTINATION "bin/client_server")
-
-endforeach( testsourcefile ${APP_SOURCES} )
+    endforeach( testsourcefile ${APP_SOURCES} )
+else()
+    message(WARNING "socket headers not found in system.")
+endif(ARPA_HEADERS OR WINSOCK_HEADER)
diff --git a/numerical_methods/CMakeLists.txt b/numerical_methods/CMakeLists.txt
index 4bc4f7af..5bfaafd1 100644
--- a/numerical_methods/CMakeLists.txt
+++ b/numerical_methods/CMakeLists.txt
@@ -5,11 +5,15 @@ file( GLOB APP_SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.c )
 # file( GLOB APP_SOURCES ${CMAKE_SOURCE_DIR}/*.c )
 # AUX_SOURCE_DIRECTORY(${CMAKE_CURRENT_SOURCE_DIR} APP_SOURCES)
 
-set (no_msvc "newton_raphson_root.c" "durand_kerner_roots.c")
+# List of files that use complex.h and complex data type
+set (NEED_COMPLEX 
+    "newton_raphson_root.c" 
+    "durand_kerner_roots.c"
+)
 
 foreach( testsourcefile ${APP_SOURCES} )
-    # Do not compile these files that use complex.h on MSVC
-    if ( ${testsourcefile} IN_LIST no_msvc AND MSVC)
+    # compile files that use complex.h only if available
+    if ( ${testsourcefile} IN_LIST NEED_COMPLEX AND NOT HAS_COMPLEX_TYPE)
         continue()
     endif()
     string( REPLACE ".c" "" testname ${testsourcefile} )
diff --git a/sorting/CMakeLists.txt b/sorting/CMakeLists.txt
index e3ff0d66..2c9e74ec 100644
--- a/sorting/CMakeLists.txt
+++ b/sorting/CMakeLists.txt
@@ -1,7 +1,3 @@
-if(USE_OPENMP)
-    find_package(OpenMP)
-endif()
-
 # If necessary, use the RELATIVE flag, otherwise each source file may be listed
 # with full pathname. RELATIVE may makes it easier to extract an executable name
 # automatically.