build: write binaries to bin folder

.gitignore

@@ -1,2 +1,3 @@
-/build
+/.build
 /.cache
+/bin

CMakeLists.txt

@@ -31,6 +31,12 @@ target_include_directories(
 
 target_link_libraries(book_exercises PRIVATE chapter_02)
 
+set_target_properties(
+  book_exercises
+  PROPERTIES ARCHIVE_OUTPUT_DIRECTORY "${PROJECT_SOURCE_DIR}/bin"
+             RUNTIME_OUTPUT_DIRECTORY "${PROJECT_SOURCE_DIR}/bin"
+             RUNTIME_OUTPUT_DIRECTORY "${PROJECT_SOURCE_DIR}/bin")
+
 if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
   add_subdirectory(tests)
 endif()

bootstrap.sh

@@ -1,3 +1,3 @@
 #!/usr/bin/env sh
 
-cmake -S . -B build -G Ninja -D CMAKE_EXPORT_COMPILE_COMMANDS=ON
+cmake -S . -B .build -G Ninja -D CMAKE_EXPORT_COMPILE_COMMANDS=ON

build.sh

@@ -1,3 +1,3 @@
 #!/usr/bin/env sh 
 
-cmake --build build 
+cmake --build .build 

test.sh

@@ -1,3 +1,3 @@
 #!/usr/bin/env sh 
 
-cmake --build build && cmake --build build --target test 
+cmake --build .build && cmake --build .build --target test