diff --git a/CMakeLists.txt b/CMakeLists.txt
index 982eb95..9732d65 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,10 @@
-project(advanced_C_standard_library)
-cmake_minimum_required(VERSION 3.0)
+project(advanced_C_standard_library C)
+set_property(GLOBAL PROPERTY C_STANDARD 99)
+cmake_minimum_required(VERSION 3.9)
 include_directories(src)
 file(GLOB SOURCES "src/*.c")
 add_executable(test.out ${SOURCES})
-install(TARGETS DESTINATION ${CMAKE_SOURCE_DIR})
+find_program(CCACHE_PROGRAM ccache)
+if(CCACHE_PROGRAM)
+    set(CMAKE_C_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")
+endif()
diff --git a/src/main.c b/src/main.c
index 8b385c4..e921ebe 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,4 +1,4 @@
 #include <stdio.h>
 int main() {
-	printf("%s", "baum\n");
+	printf("baum\n");
 }