add reverse string sample code

egendron93 · egendron93 · commit 905cf76bb942 · 2021-06-28T21:47:39.000Z
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -1,6 +1,8 @@
 cmake_minimum_required(VERSION 3.10)
 project(hello_world VERSION 0.0.0)
 
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
 set(ENABLE_TESTING "Add the tests subdirectory to the build." OFF)
 
 add_subdirectory(src)
diff --git a/conanfile.py b/conanfile.py
@@ -6,25 +6,31 @@ class HelloWorldConan(ConanFile):
   version = "0.0.0"
   url = ""
   settings = "os", "compiler", "build_type", "arch"
-  #generators = {"cmake_find_package", "BazelDeps", "BazelToolchain"}
-  generators = {"BazelDeps", "BazelToolchain"}
+  generators = {"cmake_find_package"}
+  # generators = {"BazelDeps", "BazelToolchain"}
   options = {"enable_testing":[True, False]}
   default_options = {"enable_testing": False}
   exports_sources = {"src/**", "tests/**", "CMakeLists.txt"}
 
   def requirements(self):
     self.requires.add("boost/1.73.0")
+    self.requires.add("ms-gsl/3.1.0")
     if self.options.enable_testing:
       self.requires.add("gtest/1.8.1")
 
   def build(self):
-    # cmake = CMake(self)
-    # cmake.definitions["ENABLE_TESTING"] = "ON" if self.options.enable_testing else "OFF"
-    # cmake.configure()
-    # cmake.build()
-    bazel = Bazel(self)
-    bazel.configure()
-    bazel.build(label="//...", args="--sandbox_debug")
+    cmake = CMake(self)
+    cmake.definitions["ENABLE_TESTING"] = "ON" if self.options.enable_testing else "OFF"
+    cmake.configure()
+    cmake.build()
+
+
+    # bazel = Bazel(self)
+    # bazel.configure()
+    # # build command does not seem to be applying args yet
+    # # need to configure toolchain to used c++17 or above
+    # # https://docs.bazel.build/versions/main/tutorial/cc-toolchain-config.html#configuring-the-c-toolchain
+    # bazel.build(label="//...", args="--config=clang_config")
 
   def package(self):
     self.copy("*.hpp", dst="include/", src="src/include/")
diff --git a/src/BUILD.bazel b/src/BUILD.bazel
@@ -6,5 +6,6 @@ cc_library(
     name = "hello_world",
     srcs = glob(["*.cpp"]),
     hdrs = glob(["include/*.hpp"]),
-    strip_include_prefix = "include"
+    strip_include_prefix = "include",
+    deps = ["@ms-gsl//:ms-gsl"]
 )
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
@@ -1,9 +1,11 @@
 cmake_minimum_required(VERSION 3.10)
 
 find_package(Boost 1.73.0 REQUIRED)
+find_package(Microsoft.GSL 3.1.0 REQUIRED)
 
 add_library(hello_world 
     hello_world.cpp
+    string_reversal.cpp
 )
 
 target_include_directories(hello_world PUBLIC
@@ -14,7 +16,8 @@ target_include_directories(hello_world PUBLIC
 target_compile_features(hello_world PUBLIC cxx_std_20)
 
 target_link_libraries(hello_world PUBLIC 
-    Boost::Boost 
+    Boost::Boost
+    Microsoft.GSL::Microsoft.GSL
 )
 
 include(CheckIPOSupported)
diff --git a/src/include/string_reversal.hpp b/src/include/string_reversal.hpp
@@ -0,0 +1,38 @@
+/**
+ * @file string_reversal.hpp
+ * @date 2021-06-28
+ * @brief Write a function that reverses a string. 
+ * The input string is given as an array of characters s.
+ * @link https://leetcode.com/problems/reverse-string/
+ * @note Would obviously just use std::reverse algorithm
+ * https://en.cppreference.com/w/cpp/algorithm/reverse
+ */
+
+#ifndef STRING_REVERSAL_HPP
+#define STRING_REVERSAL_HPP
+
+#include <array>
+#include <string>
+
+namespace string_reversal {
+
+constexpr auto kPrintableAsciiCount = size_t{95};
+
+constexpr std::array<char, kPrintableAsciiCount> GetPrintableAsciiCharacters();
+
+bool IsPrintableAsciiCharacters(std::string& s);
+
+/**
+ * @brief Reverses a string of characters.
+ * @pre 1 <= s.length <= 10^5
+ * @pre s[i] is a printable ascii character. (this is more of an assertion)
+ * @note Do not allocate extra space. Modify the input in-place with O(1) extra 
+ *  memory.
+ * @note Time complexity: O(N)
+ * @note Space complexity: O(1)
+ */
+void ReverseString(std::string& s);
+
+} /* namespace hello */
+
+ #endif /* STRING_REVERSAL_HPP */
diff --git a/src/string_reversal.cpp b/src/string_reversal.cpp
@@ -0,0 +1,47 @@
+/**
+ * @file string_reversal.cpp
+ * @date 2021-06-28
+ */
+
+#include <string_reversal.hpp>
+
+#include <gsl/gsl>
+
+namespace string_reversal {
+
+constexpr std::array<char, kPrintableAsciiCount> GetPrintableAsciiCharacters() {
+    auto printable_ascii = std::array<char, kPrintableAsciiCount>{};
+    auto index = size_t{0};
+    // https://en.cppreference.com/w/cpp/language/ascii
+    for (char i = ' '; i <= '~'; ++i) {
+        printable_ascii[index] = i;
+        index++;
+    }
+    return printable_ascii;
+}
+
+constexpr std::array<char, kPrintableAsciiCount> kPrintableAsciiCharacters{
+    GetPrintableAsciiCharacters()};
+
+bool IsPrintableAsciiCharacters(std::string& s) {
+    const auto printable_ascii = std::string{kPrintableAsciiCharacters.begin(), 
+                                             kPrintableAsciiCharacters.end()};
+    return s.find_first_not_of(printable_ascii) == std::string_view::npos;
+}
+
+void ReverseString(std::string& s) {
+    Expects(s.length() >= 1 && s.length() <= 100000);
+    Expects(IsPrintableAsciiCharacters(s));
+    auto left = size_t{0};
+    auto right = size_t{s.size() - 1};
+        
+    while (left < right) {
+        auto temp = s[left];
+        s[left] = s[right];
+        s[right] = temp;
+        left++;
+        right--;
+    }
+}
+
+} /* namespace hello */
diff --git a/tests/unit/CMakeLists.txt b/tests/unit/CMakeLists.txt
@@ -9,6 +9,7 @@ endif()
 
 add_executable(hello_world_unit
     src/hello_world_unit.cpp
+    src/string_reversal_unit.cpp
     src/main.cpp
 )
 
diff --git a/tests/unit/src/hello_world_unit.cpp b/tests/unit/src/hello_world_unit.cpp
@@ -4,12 +4,12 @@
  * @date 2020-07-01
  */
 
- #include <gtest/gtest.h>
+#include <gtest/gtest.h>
 
- #include <hello_world.hpp>
+#include <hello_world.hpp>
 
- using namespace hello;
+using namespace hello;
 
- TEST(HelloWorldUnit, GetHelloWorldString_ReturnsHelloWorld) {
-     ASSERT_EQ("hello world", GetHelloWorldString());
- }
+TEST(HelloWorldUnit, GetHelloWorldString_ReturnsHelloWorld) {
+    ASSERT_EQ("hello world", GetHelloWorldString());
+}
diff --git a/tests/unit/src/string_reversal_unit.cpp b/tests/unit/src/string_reversal_unit.cpp
@@ -0,0 +1,52 @@
+/**
+ * @file string_reversal_unit.cpp
+ * @author Edwin Gendron
+ * @date 2021-06-28
+ */
+
+#include <gtest/gtest.h>
+
+#include <string_reversal.hpp>
+
+using namespace string_reversal;
+
+/**
+ * @pre empty string
+ * @post program terminated
+ */
+TEST(StringReversalUnit, ReverseStringEmptyStringExceptionThrown) {
+    auto empty_string = std::string{};
+    ASSERT_DEATH(ReverseString(empty_string), "");
+}
+
+/**
+ * @pre string of size 1
+ * @post string remains the same
+ */
+TEST(StringReversalUnit, ReverseStringStringSizeOneExceptionThrown) {
+    auto test_string = std::string{"a"};
+    auto temp_test_string = std::string{test_string};
+    ReverseString(test_string);
+    ASSERT_EQ(temp_test_string, test_string);
+}
+
+/**
+ * @pre string of size 100005, 5 chars too large.
+ * @post program terminated
+ */
+TEST(StringReversalUnit, ReverseStringStringSizeTooLargeExceptionThrown) {
+    auto test_string = std::string(100005, 'a');
+    ASSERT_DEATH(ReverseString(test_string), "");
+}
+
+/**
+ * @pre string to reverse within the specified size and larger than 1 char
+ * @post string is reversed
+ */
+TEST(StringReversalUnit, ReverseStringStringSizeAcceptableAndGreaterThanOneReversedStringReturned) {
+    auto test_string = std::string{"abcdefghijklmnopqrstuvwxyz"};
+    const auto expected_reversed_result = 
+        std::string{"zyxwvutsrqponmlkjihgfedcba"};
+    ReverseString(test_string);
+    ASSERT_EQ(test_string, expected_reversed_result);
+}

Original file line number	Diff line number	Diff line change
`@@ -6,5 +6,6 @@ cc_library(`
`6`	`6`	`name = "hello_world",`
`7`	`7`	`srcs = glob(["*.cpp"]),`
`8`	`8`	`hdrs = glob(["include/*.hpp"]),`
`9`		`- strip_include_prefix = "include"`
	`9`	`+ strip_include_prefix = "include",`
	`10`	`+ deps = ["@ms-gsl//:ms-gsl"]`
`10`	`11`	`)`
Original file line number	Diff line number	Diff line change
`@@ -9,6 +9,7 @@ endif()`
`9`	`9`
`10`	`10`	`add_executable(hello_world_unit`
`11`	`11`	`src/hello_world_unit.cpp`
	`12`	`+ src/string_reversal_unit.cpp`
`12`	`13`	`src/main.cpp`
`13`	`14`	`)`
`14`	`15`