Add palindrome in C

CMakeLists.txt

@@ -6,6 +6,10 @@
 
 cmake_minimum_required(VERSION 3.26)
 
+set(CMAKE_C_STANDARD 90)
+set(CMAKE_C_STANDARD_REQUIRED ON)
+set(CMAKE_C_EXTENSIONS OFF)
+
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
@@ -17,7 +21,7 @@ set(
 
 project(
   ForFun
-  LANGUAGES CXX
+  LANGUAGES C CXX
 )
 
 add_library(
@@ -45,6 +49,21 @@ target_include_directories(
 
 link_libraries(forfun)
 
+add_library(
+  forfun_c
+  SHARED
+  "include/forfun/palindrome.h"
+  "src/palindrome.c"
+)
+
+target_include_directories(
+  forfun_c
+  PUBLIC
+  "${CMAKE_SOURCE_DIR}/include"
+)
+
+link_libraries(forfun_c)
+
 add_executable(
   fizzbuzz
   "test/fizzbuzz.cpp"
@@ -60,6 +79,11 @@ add_executable(
   "test/palindrome.cpp"
 )
 
+add_executable(
+  palindrome_c
+  "test/palindrome.c"
+)
+
 add_executable(
   palindromic_number
   "test/palindromic_number.cpp"

README.md

@@ -1,6 +1,6 @@
 # Miscellaneous coding problem solutions
 
-Solutions written in C++ (C++17 and C++20) for various coding problems.
+Solutions for various coding problems, written in C90, C++17, and C++20.
 
 The solutions are not necessarily optimal or meant as best practice.
 

benchmark/palindrome_benchmark.cpp

@@ -12,6 +12,7 @@
 
 #include <string_view>
 
+#include "forfun/palindrome.h"
 #include "forfun/palindrome.hpp"
 
 TEST_CASE("forfun::palindrome benchmarking") {
@@ -24,6 +25,14 @@ TEST_CASE("forfun::palindrome benchmarking") {
 
             .title("Palindrome (case-sensitive)")
 
+            .run(
+                NAMEOF_RAW(::is_palindrome).c_str(),
+                [&palindrome]() {
+                    auto r{
+                        ::is_palindrome(palindrome.data(), palindrome.size())};
+                    ankerl::nanobench::doNotOptimizeAway(r);
+                })
+
             .run(
                 NAMEOF_RAW(forfun::palindrome::fast::is_palindrome).c_str(),
                 [&palindrome]() {
@@ -63,6 +72,14 @@ TEST_CASE("forfun::palindrome benchmarking") {
 
             .title("Palindrome (case-insensitive)")
 
+            .run(
+                NAMEOF_RAW(::is_palindrome_ci).c_str(),
+                [&palindrome]() {
+                    auto r{::is_palindrome_ci(
+                        palindrome.data(), palindrome.size())};
+                    ankerl::nanobench::doNotOptimizeAway(r);
+                })
+
             .run(
                 NAMEOF_RAW(forfun::palindrome::fast::is_palindrome_ci).c_str(),
                 [&palindrome]() {

include/forfun/palindrome.h

@@ -0,0 +1,31 @@
+/*
+Copyright (c) Omar Boukli-Hacene. All rights reserved.
+Distributed under an MIT-style license that can be
+found in the LICENSE file.
+*/
+
+/* SPDX-License-Identifier: MIT */
+
+/*
+Problem reference:
+https://en.wikipedia.org/wiki/Palindrome
+*/
+
+#ifndef FORFUN_PALINDROME_H_
+#define FORFUN_PALINDROME_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+#include <stddef.h>
+
+int is_palindrome(char const* const str, size_t const size);
+
+int is_palindrome_ci(char const* const str, size_t const size);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* FORFUN_PALINDROME_H_ */

src/palindrome.c

@@ -0,0 +1,40 @@
+/*
+Copyright (c) Omar Boukli-Hacene. All rights reserved.
+Distributed under an MIT-style license that can be
+found in the LICENSE file.
+*/
+
+/* SPDX-License-Identifier: MIT */
+
+#include "forfun/palindrome.h"
+
+#include <ctype.h>
+
+int is_palindrome(char const* const str, size_t const size) {
+    size_t const end = size - 1;
+    size_t const mid = size / 2;
+
+    size_t i;
+    for (i = 0; i < mid; ++i) {
+        if (str[i] != str[end - i]) {
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
+int is_palindrome_ci(char const* const str, size_t const size) {
+    size_t const end = size - 1;
+    size_t const mid = size / 2;
+
+    size_t i;
+    for (i = 0; i < mid; ++i) {
+        if (tolower((unsigned char)str[i])
+            != tolower((unsigned char)str[end - i])) {
+            return 0;
+        }
+    }
+
+    return 1;
+}

test/palindrome.c

@@ -0,0 +1,94 @@
+/*
+Copyright (c) Omar Boukli-Hacene. All rights reserved.
+Distributed under an MIT-style license that can be
+found in the LICENSE file.
+*/
+
+/* SPDX-License-Identifier: MIT */
+
+#include "forfun/palindrome.h"
+
+#include <assert.h>
+#include <string.h>
+
+void test_palindrome() {
+    {
+        char const* const s = "";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome(s, len);
+        assert(f_palindrome);
+    }
+
+    {
+        char const* const s = "\xb8Y\xb8";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome(s, len);
+        assert(f_palindrome);
+    }
+
+    {
+        char const* const s = "aa";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome(s, len);
+        assert(f_palindrome);
+    }
+
+    {
+        char const* const s = "aba";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome(s, len);
+        assert(f_palindrome);
+    }
+
+    {
+        char const* const s = "a b a";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome(s, len);
+        assert(f_palindrome);
+    }
+
+    {
+        char const* const s = "101";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome(s, len);
+        assert(f_palindrome);
+    }
+
+    {
+        char const* const s = "tattarrattat";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome(s, len);
+        assert(f_palindrome);
+    }
+
+    {
+        char const* const s = "dummy";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome(s, len);
+        assert(f_palindrome == 0);
+    }
+}
+
+void test_palindrome_ci() {
+    {
+        char const* const s = "Aa";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome_ci(s, len);
+        assert(f_palindrome);
+    }
+
+    {
+        char const* const s = "Aab4'{x{'4BaA";
+        size_t const len = strlen(s);
+        int const f_palindrome = is_palindrome_ci(s, len);
+        assert(f_palindrome);
+    }
+}
+
+int main() {
+    test_palindrome();
+
+    test_palindrome_ci();
+
+    return 0;
+}