[cpp] Fix root project build and dependencies.

cpp/CMakeLists.txt

@@ -1,6 +1,6 @@
 ################################################################################
 ## Author: Shaun Reed                                                         ##
-## Legal: All Content (c) 2022 Shaun Reed, all rights reserved                ##
+## Legal: All Content (c) 2025 Shaun Reed, all rights reserved                ##
 ## About: A root project for practicing C++                                   ##
 ##        This project can be built to debug and run all nested projects      ##
 ##        Or, any subdirectory with a project() statement can be selected     ##
@@ -16,10 +16,32 @@ project(
     DESCRIPTION "A root project for several small cpp practice projects"
     LANGUAGES   CXX
 )
+message(STATUS "[Klips] Configuring example: ${PROJECT_NAME}")
 
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 add_compile_options("-Wall")
 
+option(KLIPS_CCACHE "Enable ccache" ON)
+
+if (KLIPS_CCACHE)
+  find_program(SCCACHE_PATH sccache)
+  if(SCCACHE_PATH)
+    message(STATUS "[Klips] Found sccache: ${SCCACHE_PATH}")
+    set(CMAKE_CXX_COMPILER_LAUNCHER ${SCCACHE_PATH})
+    set(CMAKE_C_COMPILER_LAUNCHER ${SCCACHE_PATH})
+  else()
+    message(STATUS "[Klips] Failed to find sccache, falling back to ccache.")
+    find_program(CCACHE_PATH ccache)
+    if(CCACHE_PATH)
+      message(STATUS "[Klips] Found ccache: ${CCACHE_PATH}")
+      set(CMAKE_CXX_COMPILER_LAUNCHER ${CCACHE_PATH})
+      set(CMAKE_C_COMPILER_LAUNCHER ${CCACHE_PATH})
+    else()
+      message(WARNING "[Klips] Failed to find sccache and ccache. Compilation will not be cached.")
+    endif()
+  endif()
+endif()
+
 add_subdirectory(algorithms)
 add_subdirectory(catch2)
 add_subdirectory(cmake-example)
@@ -28,4 +50,15 @@ add_subdirectory(datastructs)
 add_subdirectory(graphics)
 add_subdirectory(multithreading)
 add_subdirectory(patterns)
-add_subdirectory(qt)
+
+find_package(Qt6 COMPONENTS UiPlugin Core Gui Widgets)
+if (NOT Qt6_FOUND)
+  message(
+      WARNING
+      "[Klips] Qt examples will not be built.\n"
+      "On Ubuntu 24.04 Qt6 can be installed using apt:\n"
+      "  sudo apt install qt6-base-dev qt6-tools-dev\n"
+  )
+else()
+  add_subdirectory(qt)
+endif()