diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4d9001a..6df1f64 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,16 +1,22 @@
 CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 PROJECT(SGP4)
 
-file(GLOB SRCS libsgp4/*.cpp)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wextra")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wshadow")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wnon-virtual-dtor")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-long-long")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wcast-align")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-conversion")
 
 include_directories(libsgp4)
 
-add_library(sgp4 STATIC ${SRCS})
-add_executable(sattrack sattrack/sattrack.cpp)
-target_link_libraries(sattrack sgp4 rt)
-add_executable(runtest runtest/runtest.cpp)
-target_link_libraries(runtest sgp4 rt)
-add_executable(passpredict passpredict/passpredict.cpp)
-target_link_libraries(passpredict sgp4 rt)
+add_subdirectory(libsgp4)
+add_subdirectory(sattrack)
+add_subdirectory(runtest)
+add_subdirectory(passpredict)
 
 file(COPY SGP4-VER.TLE DESTINATION ${PROJECT_BINARY_DIR})
diff --git a/libsgp4/CMakeLists.txt b/libsgp4/CMakeLists.txt
new file mode 100644
index 0000000..a58a7c3
--- /dev/null
+++ b/libsgp4/CMakeLists.txt
@@ -0,0 +1,19 @@
+set(SRCS
+    CoordGeodetic.cpp
+    CoordTopocentric.cpp
+    DateTime.cpp
+    DecayedException.cpp
+    Eci.cpp
+    Globals.cpp
+    Observer.cpp
+    OrbitalElements.cpp
+    SGP4.cpp
+    SatelliteException.cpp
+    SolarPosition.cpp
+    TimeSpan.cpp
+    Tle.cpp
+    TleException.cpp
+    Util.cpp
+    Vector.cpp)
+
+add_library(sgp4 STATIC ${SRCS})
diff --git a/libsgp4/Tle.cpp b/libsgp4/Tle.cpp
index b7f6cd3..07f62b6 100644
--- a/libsgp4/Tle.cpp
+++ b/libsgp4/Tle.cpp
@@ -177,7 +177,7 @@ void Tle::ExtractInteger(const std::string& str, unsigned int& val)
         if (isdigit(*i))
         {
             found_digit = true;
-            temp = (temp * 10) + (static_cast<unsigned char>(*i) - '0');
+            temp = (temp * 10) + static_cast<unsigned int>(*i - '0');
         }
         else if (found_digit)
         {
diff --git a/passpredict/CMakeLists.txt b/passpredict/CMakeLists.txt
new file mode 100644
index 0000000..c0f0b85
--- /dev/null
+++ b/passpredict/CMakeLists.txt
@@ -0,0 +1,8 @@
+set(SRCS
+    passpredict.cpp)
+
+add_executable(passpredict
+    ${SRCS})
+target_link_libraries(passpredict
+    sgp4
+    rt)
diff --git a/runtest/CMakeLists.txt b/runtest/CMakeLists.txt
new file mode 100644
index 0000000..c446be3
--- /dev/null
+++ b/runtest/CMakeLists.txt
@@ -0,0 +1,8 @@
+set(SRCS
+    runtest.cpp)
+
+add_executable(runtest
+    ${SRCS})
+target_link_libraries(runtest
+    sgp4
+    rt)
diff --git a/sattrack/CMakeLists.txt b/sattrack/CMakeLists.txt
new file mode 100644
index 0000000..c61139f
--- /dev/null
+++ b/sattrack/CMakeLists.txt
@@ -0,0 +1,8 @@
+set(SRCS
+    sattrack.cpp)
+
+add_executable(sattrack
+    ${SRCS})
+target_link_libraries(sattrack
+    sgp4
+    rt)
diff --git a/sattrack/sattrack.cpp b/sattrack/sattrack.cpp
index 77e5f89..9404dfb 100644
--- a/sattrack/sattrack.cpp
+++ b/sattrack/sattrack.cpp
@@ -32,7 +32,7 @@ int main()
 
     std::cout << tle << std::endl;
 
-    while (true)
+    for (int i = 0; i < 10; ++i)
     {
         /*
          * current time