diff --git a/CMakeLists.txt b/CMakeLists.txt
index 78cea40..de19ed8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,11 +9,11 @@ project(
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
-add_subdirectory(src/cppunit)
+add_subdirectory(src/ccunit)
 add_subdirectory(src/prep)
 
-add_executable(main src/main.cpp)
-add_library(lib src/lib.cpp src/lib.hh)
+add_executable(main src/main.cc)
+add_library(lib src/lib.cc src/lib.hh)
 target_link_libraries(main PUBLIC lib)
 target_link_libraries(lib PUBLIC prepLib)
 target_include_directories(main PUBLIC "${PROJECT_BINARY_DIR}"
@@ -28,7 +28,7 @@ FetchContent_Declare(
 )
 FetchContent_MakeAvailable(googletest)
 
-add_executable(runtests src/test.cpp)
+add_executable(runtests src/test.cc)
 target_link_libraries(runtests PUBLIC lib gtest gtest_main)
 target_include_directories(runtests PUBLIC "${PROJECT_BINARY_DIR}")
 
diff --git a/src/cppunit/CMakeLists.txt b/src/cppunit/CMakeLists.txt
index 3e8a2ba..9d4a5a9 100644
--- a/src/cppunit/CMakeLists.txt
+++ b/src/cppunit/CMakeLists.txt
@@ -1 +1 @@
-add_library(cppunit cppunit.cpp cppunit.hh)
+add_library(ccunit ccunit.cc ccunit.hh)
diff --git a/src/cppunit/cppunit.cpp b/src/cppunit/cppunit.cc
similarity index 100%
rename from src/cppunit/cppunit.cpp
rename to src/cppunit/cppunit.cc
diff --git a/src/lib.cpp b/src/lib.cc
similarity index 100%
rename from src/lib.cpp
rename to src/lib.cc
diff --git a/src/main.cpp b/src/main.cc
similarity index 100%
rename from src/main.cpp
rename to src/main.cc
diff --git a/src/prep/CMakeLists.txt b/src/prep/CMakeLists.txt
index 6d9cc1d..599d6df 100644
--- a/src/prep/CMakeLists.txt
+++ b/src/prep/CMakeLists.txt
@@ -1 +1 @@
-add_library(prepLib prep.cpp prep.hh timeUtils.cpp timeUtils.hh)
+add_library(prepLib prep.cc prep.hh timeUtils.cc timeUtils.hh)
diff --git a/src/prep/prep.cpp b/src/prep/prep.cc
similarity index 100%
rename from src/prep/prep.cpp
rename to src/prep/prep.cc
diff --git a/src/prep/timeUtils.cpp b/src/prep/timeUtils.cc
similarity index 100%
rename from src/prep/timeUtils.cpp
rename to src/prep/timeUtils.cc
diff --git a/src/test.cpp b/src/test.cc
similarity index 100%
rename from src/test.cpp
rename to src/test.cc