diff --git a/CMakeLists.txt b/CMakeLists.txt
index 952b43b..d6fed49 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,7 +4,7 @@ if(POLICY CMP0048)
     cmake_policy(SET CMP0048 NEW)
 endif()
 
-project(tree-gen LANGUAGES C CXX)
+project(tree-gen LANGUAGES CXX)
 
 # If tree-gen was already included elsewhere in the project, don't include it
 # again. There should be only one place for it and one version per project.
diff --git a/examples/directory/CMakeLists.txt b/examples/directory/CMakeLists.txt
index 0e96ec8..9cff71e 100644
--- a/examples/directory/CMakeLists.txt
+++ b/examples/directory/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
 
-project(directory-example C CXX)
+project(directory-example CXX)
 
 include(../../cmake/generate_tree.cmake)
 
diff --git a/examples/directory/main.cpp b/examples/directory/main.cpp
index 8b0fed5..910bf57 100644
--- a/examples/directory/main.cpp
+++ b/examples/directory/main.cpp
@@ -1,9 +1,10 @@
 #include "../utils.hpp"
 
-#include <cstdio>
-#include <iostream>
+#include <fmt/core.h>
+#include <fstream>
+#include <ios>
 #include <sstream>  // ostringstream
-#include <stdexcept>
+#include <string>
 
 // Include the generated file.
 #include "directory.hpp"
@@ -238,15 +239,15 @@ int main() {
     int count = 0;
     for (char c : cbor) {
         if (count == 16) {
-            std::printf("\n");
+            fmt::print("\n");
             count = 0;
         } else if (count > 0 && count % 4 == 0) {
-            std::printf(" ");
+            fmt::print(" ");
         }
-        std::printf("%02X ", (uint8_t)c);
+        fmt::print("{:02X} ", static_cast<uint8_t>(c));
         count++;
     }
-    std::printf("\n");
+    fmt::print("\n");
     MARKER
 
     // You can pull that through http://cbor.me and https://jsonformatter.org
@@ -277,8 +278,7 @@ int main() {
         R"({"target":"...","name":"SomeUser"}}],"name":""}},"name":"evil link to C:"}}],"na)"
         R"(me":""}}}}]}})"
     );
-    std::printf("%s", oss.str().c_str());
-    std::printf("\n");
+    fmt::print("{}\n", oss.str());
     MARKER
 
     // Note that equality for two link edges is satisfied only if they point to
diff --git a/examples/interpreter/CMakeLists.txt b/examples/interpreter/CMakeLists.txt
index 3954d7c..8df0e07 100644
--- a/examples/interpreter/CMakeLists.txt
+++ b/examples/interpreter/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
 
-project(interpreter-example C CXX)
+project(interpreter-example CXX)
 
 include(../../cmake/generate_tree.cmake)
 
diff --git a/examples/interpreter/main.cpp b/examples/interpreter/main.cpp
index c9dd967..53668f5 100644
--- a/examples/interpreter/main.cpp
+++ b/examples/interpreter/main.cpp
@@ -1,9 +1,9 @@
 #include "../utils.hpp"
 
-#include <cstdio>
-#include <iostream>
+#include <fmt/core.h>
 #include <sstream>  // ostringstream
-#include <stdexcept>
+#include <stdexcept>  // runtime_error
+#include <string>
 
 // Include the generated files.
 #include "value.hpp"
@@ -201,8 +201,7 @@ int main() {
         R"(alue":"2","source_location":"test:1:5"}},"source_location":"test:1:1"}}],"source)"
         R"(_location":"test:1:1"}})"
     );
-    std::printf("%s", oss.str().c_str());
-    std::printf("\n");
+    fmt::print("{}\n", oss.str());
     MARKER
 
     // Note that we can still use these pointers despite ownership having been
diff --git a/examples/utils.hpp b/examples/utils.hpp
index 09550ab..151d94b 100644
--- a/examples/utils.hpp
+++ b/examples/utils.hpp
@@ -1,9 +1,12 @@
 #pragma once
 
+#include <fmt/core.h>
+#include <stdexcept>  // runtime_error
+
 #define ASSERT(x)                                                                                                       \
     do {                                                                                                                \
         if (!(x)) {                                                                                                     \
-            throw std::runtime_error("assertion failed: " #x " is false at " __FILE__ ":" + std::to_string(__LINE__));  \
+            throw std::runtime_error{ fmt::format("assertion failed: {} is false at {}:{}", #x, __FILE__, __LINE__) };  \
         }                                                                                                               \
     } while (0)
 
@@ -11,10 +14,10 @@
     do {                                                                                                                \
         try {                                                                                                           \
             x;                                                                                                          \
-            throw std::runtime_error("assertion failed: no exception at " __FILE__ ":" + std::to_string(__LINE__));     \
+            throw std::runtime_error{ fmt::format("assertion failed: no exception at {}:{}", __FILE__, __LINE__) } ;    \
         } catch (exc &e) {                                                                                              \
-            std::cout << #exc << " exception message: " << e.what() << std::endl;                                       \
+            fmt::print("{} exception message: {}\n", #exc, e.what());                                                   \
         }                                                                                                               \
     } while (0)
 
-#define MARKER std::cout << "###MARKER###" << std::endl;
+#define MARKER fmt::print("###MARKER###\n");
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index ed93629..69b8775 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -2,6 +2,8 @@ cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
 
 # Packages
 include(FetchContent)
+
+# gtest
 find_package(GTest)
 if(NOT GTest_FOUND)
     FetchContent_Declare(gtest
@@ -10,6 +12,7 @@ if(NOT GTest_FOUND)
     )
     set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
     FetchContent_MakeAvailable(gtest)
+    add_library(gtest::gtest ALIAS gtest)
 endif()
 include(GoogleTest)