exercism · ahans · May 12, 2025 · May 10, 2025
diff --git a/bin/make-stub-files.sh b/bin/make-stub-files.sh
@@ -21,10 +21,8 @@ for exercise_dir in "${exercises_dir}"/*; do
     header="$exercise_name.h"
     source="$exercise_name.cpp"
     if ! test -f "$header"; then
-        printf "#if !defined(${exercise_name^^}_H)\n" >> $header
-        printf "#define ${exercise_name^^}_H\n" >> $header
+        printf "#pragma once\n" >> $header
         printf "\nnamespace $exercise_name {\n\n}  // namespace $exercise_name\n" >> $header
-        printf "\n#endif // ${exercise_name^^}_H" >> $header
         git add $header
     fi
     if ! test -f "$source"; then

diff --git a/exercises/practice/acronym/.meta/example.h b/exercises/practice/acronym/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(ACRONYM_H)
-#define ACRONYM_H
+#pragma once
 
 #include <string>
 
@@ -8,5 +7,3 @@ namespace acronym {
 std::string acronym(std::string const&);
 
 }
-
-#endif
diff --git a/exercises/practice/acronym/acronym.h b/exercises/practice/acronym/acronym.h
@@ -1,10 +1,7 @@
-#if !defined(ACRONYM_H)
-#define ACRONYM_H
+#pragma once
 
 namespace acronym {
 
 // TODO: add your solution here
 
 }  // namespace acronym
-
-#endif  // ACRONYM_H
diff --git a/exercises/practice/all-your-base/.meta/example.h b/exercises/practice/all-your-base/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(ALL_YOUR_BASE_H)
-#define ALL_YOUR_BASE_H
+#pragma once
 
 #include <vector>
 
@@ -9,5 +8,3 @@ std::vector<unsigned int> convert(unsigned int input_base,
                                   const std::vector<unsigned int>& input_digits,
                                   unsigned int output_base);
 }
-
-#endif
diff --git a/exercises/practice/all-your-base/all_your_base.h b/exercises/practice/all-your-base/all_your_base.h
@@ -1,10 +1,7 @@
-#if !defined(ALL_YOUR_BASE_H)
-#define ALL_YOUR_BASE_H
+#pragma once
 
 namespace all_your_base {
 
 // TODO: add your solution here
 
 }  // namespace all_your_base
-
-#endif  // ALL_YOUR_BASE_H
diff --git a/exercises/practice/allergies/.meta/example.h b/exercises/practice/allergies/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(ALLERGIES_H)
-#define ALLERGIES_H
+#pragma once
 
 #include <map>
 #include <string>
@@ -23,5 +22,3 @@ class allergy_test {
 };
 
 }  // namespace allergies
-
-#endif
diff --git a/exercises/practice/allergies/allergies.h b/exercises/practice/allergies/allergies.h
@@ -1,10 +1,7 @@
-#if !defined(ALLERGIES_H)
-#define ALLERGIES_H
+#pragma once
 
 namespace allergies {
 
 // TODO: add your solution here
 
 }  // namespace allergies
-
-#endif  // ALLERGIES_H
diff --git a/exercises/practice/anagram/.meta/example.h b/exercises/practice/anagram/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(ANAGRAM_H)
-#define ANAGRAM_H
+#pragma once
 
 #include <string>
 #include <vector>
@@ -18,5 +17,3 @@ class anagram {
 };
 
 }  // namespace anagram
-
-#endif
diff --git a/exercises/practice/anagram/anagram.h b/exercises/practice/anagram/anagram.h
@@ -1,10 +1,7 @@
-#if !defined(ANAGRAM_H)
-#define ANAGRAM_H
+#pragma once
 
 namespace anagram {
 
 // TODO: add your solution here
 
 }  // namespace anagram
-
-#endif  // ANAGRAM_H
diff --git a/exercises/practice/armstrong-numbers/.meta/example.h b/exercises/practice/armstrong-numbers/.meta/example.h
@@ -1,10 +1,7 @@
-#if !defined(ARMSTRONG_NUMBERS_H_)
-#define ARMSTRONG_NUMBERS_H_
+#pragma once
 
 namespace armstrong_numbers {
 
 bool is_armstrong_number(int number);
 
 }  // namespace armstrong_numbers
-
-#endif  // !ARMSTRONG_NUMBERS_H_
diff --git a/exercises/practice/armstrong-numbers/armstrong_numbers.h b/exercises/practice/armstrong-numbers/armstrong_numbers.h
@@ -1,10 +1,7 @@
-#if !defined(ARMSTRONG_NUMBERS_H)
-#define ARMSTRONG_NUMBERS_H
+#pragma once
 
 namespace armstrong_numbers {
 
 // TODO: add your solution here
 
 }  // namespace armstrong_numbers
-
-#endif  // ARMSTRONG_NUMBERS_H
diff --git a/exercises/practice/atbash-cipher/.meta/example.h b/exercises/practice/atbash-cipher/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(ATBASH_CIPHER_H)
-#define ATBASH_CIPHER_H
+#pragma once
 
 #include <string>
 
@@ -9,4 +8,3 @@ std::string encode(std::string const& plaintext);
 std::string decode(std::string const& ciphertext);
 
 }  // namespace atbash_cipher
-#endif
diff --git a/exercises/practice/atbash-cipher/atbash_cipher.h b/exercises/practice/atbash-cipher/atbash_cipher.h
@@ -1,10 +1,7 @@
-#if !defined(ATBASH_CIPHER_H)
-#define ATBASH_CIPHER_H
+#pragma once
 
 namespace atbash_cipher {
 
 // TODO: add your solution here
 
 }  // namespace atbash_cipher
-
-#endif  // ATBASH_CIPHER_H
diff --git a/exercises/practice/bank-account/.meta/example.h b/exercises/practice/bank-account/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(BANK_ACCOUNT_H)
-#define BANK_ACCOUNT_H
+#pragma once
 
 #include <mutex>
 
@@ -21,4 +20,3 @@ class Bankaccount {
     std::mutex mutex_{};
 };
 }  // namespace Bankaccount
-#endif  // BANK_ACCOUNT_H
diff --git a/exercises/practice/bank-account/bank_account.h b/exercises/practice/bank-account/bank_account.h
@@ -1,9 +1,6 @@
-#if !defined(BANK_ACCOUNT_H)
-#define BANK_ACCOUNT_H
+#pragma once
 
 namespace Bankaccount {
 class Bankaccount {};  // class Bankaccount
 
 }  // namespace Bankaccount
-
-#endif  // BANK_ACCOUNT_H
diff --git a/exercises/practice/beer-song/.meta/example.h b/exercises/practice/beer-song/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(BEER_SONG_H)
-#define BEER_SONG_H
+#pragma once
 
 #include <string>
 
@@ -10,5 +9,3 @@ std::string sing(unsigned begin, unsigned end);
 std::string sing(unsigned bottles);
 
 }  // namespace beer_song
-
-#endif
diff --git a/exercises/practice/beer-song/beer_song.h b/exercises/practice/beer-song/beer_song.h
@@ -1,10 +1,7 @@
-#if !defined(BEER_SONG_H)
-#define BEER_SONG_H
+#pragma once
 
 namespace beer_song {
 
 // TODO: add your solution here
 
 }  // namespace beer_song
-
-#endif  // BEER_SONG_H
diff --git a/exercises/practice/binary-search-tree/.meta/example.h b/exercises/practice/binary-search-tree/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(_BINARY_SEARCH_TREE_H_)
-#define _BINARY_SEARCH_TREE_H_
+#pragma once
 
 #include <cstdint>
 #include <memory>
@@ -211,5 +210,3 @@ void binary_tree<T>::binary_tree_iter::advance_branch_iter(state next_state) {
 }
 
 }  // namespace binary_search_tree
-
-#endif  // _BINARY_SEARCH_TREE_H_
diff --git a/exercises/practice/binary-search-tree/binary_search_tree.h b/exercises/practice/binary-search-tree/binary_search_tree.h
@@ -1,10 +1,7 @@
-#if !defined(BINARY_SEARCH_TREE_H)
-#define BINARY_SEARCH_TREE_H
+#pragma once
 
 namespace binary_search_tree {
 
 // TODO: add your solution here
 
 }  // namespace binary_search_tree
-
-#endif  // BINARY_SEARCH_TREE_H
diff --git a/exercises/practice/binary-search/.approaches/introduction.md b/exercises/practice/binary-search/.approaches/introduction.md
@@ -7,14 +7,12 @@ One approach can use a `while` loop with `if` statements.
 
 **binary_search.h**
 ```cpp
-#if !defined(BINARY_SEARCH_H)
-#define BINARY_SEARCH_H
+#pragma once
 #include <vector>
 #include <cstddef>
 namespace binary_search {
     std::size_t find (const std::vector<int>& data, int value);
 }  // namespace binary_search
-#endif // BINARY_SEARCH_H
 ```
 
 **binary_search.cpp**

diff --git a/exercises/practice/binary-search/.approaches/while-with-if-statements/content.md b/exercises/practice/binary-search/.approaches/while-with-if-statements/content.md
@@ -3,14 +3,12 @@
 
 **binary_search.h**
 ```cpp
-#if !defined(BINARY_SEARCH_H)
-#define BINARY_SEARCH_H
+#pragma once
 #include <vector>
 #include <cstddef>
 namespace binary_search {
     std::size_t find (const std::vector<int>& data, int value);
 }  // namespace binary_search
-#endif // BINARY_SEARCH_H
 ```
 
 **binary_search.cpp**

diff --git a/exercises/practice/binary-search/.meta/example.h b/exercises/practice/binary-search/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(BINARY_SEARCH_H)
-#define BINARY_SEARCH_H
+#pragma once
 
 #include <cstddef>
 #include <vector>
@@ -11,5 +10,3 @@ using std::size_t;
 size_t find(std::vector<int> const&, int const);
 
 }  // namespace binary_search
-
-#endif  // BINARY_SEARCH_H
diff --git a/exercises/practice/binary-search/binary_search.h b/exercises/practice/binary-search/binary_search.h
@@ -1,10 +1,7 @@
-#if !defined(BINARY_SEARCH_H)
-#define BINARY_SEARCH_H
+#pragma once
 
 namespace binary_search {
 
 // TODO: add your solution here
 
 }  // namespace binary_search
-
-#endif  // BINARY_SEARCH_H
diff --git a/exercises/practice/binary/.meta/example.h b/exercises/practice/binary/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(BINARY_H)
-#define BINARY_H
+#pragma once
 
 #include <string>
 
@@ -8,5 +7,3 @@ namespace binary {
 int convert(std::string const& text);
 
 }
-
-#endif
diff --git a/exercises/practice/binary/binary.h b/exercises/practice/binary/binary.h
@@ -1,10 +1,7 @@
-#if !defined(BINARY_H)
-#define BINARY_H
+#pragma once
 
 namespace binary {
 
 // TODO: add your solution here
 
 }  // namespace binary
-
-#endif  // BINARY_H
diff --git a/exercises/practice/bob/.meta/example.h b/exercises/practice/bob/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(BOB_H)
-#define BOB_H
+#pragma once
 
 #include <string>
 
@@ -8,5 +7,3 @@ namespace bob {
 std::string hey(std::string const& text);
 
 }
-
-#endif
diff --git a/exercises/practice/bob/bob.h b/exercises/practice/bob/bob.h
@@ -1,10 +1,7 @@
-#if !defined(BOB_H)
-#define BOB_H
+#pragma once
 
 namespace bob {
 
 // TODO: add your solution here
 
 }  // namespace bob
-
-#endif  // BOB_H
diff --git a/exercises/practice/circular-buffer/.meta/example.h b/exercises/practice/circular-buffer/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(CIRCULAR_BUFFER_H_)
-#define CIRCULAR_BUFFER_H_
+#pragma once
 
 #include <stdexcept>
 #include <vector>
@@ -56,5 +55,3 @@ void circular_buffer<ValueType>::push_back(ValueType item) {
 }
 
 }  // namespace circular_buffer
-
-#endif  // !CIRCULAR_BUFFER_H_
diff --git a/exercises/practice/circular-buffer/circular_buffer.h b/exercises/practice/circular-buffer/circular_buffer.h
@@ -1,10 +1,7 @@
-#if !defined(CIRCULAR_BUFFER_H)
-#define CIRCULAR_BUFFER_H
+#pragma once
 
 namespace circular_buffer {
 
 // TODO: add your solution here
 
 }  // namespace circular_buffer
-
-#endif  // CIRCULAR_BUFFER_H
diff --git a/exercises/practice/clock/.meta/example.h b/exercises/practice/clock/.meta/example.h
@@ -1,5 +1,4 @@
-#if !defined(CLOCK_H)
-#define CLOCK_H
+#pragma once
 
 #include <string>
 
@@ -28,5 +27,3 @@ inline bool operator!=(const clock& lhs, const clock& rhs) {
 }
 
 }  // namespace date_independent
-
-#endif