feat: add examples directory with first example

CMakeLists.txt

@@ -39,3 +39,7 @@ if(${COMPILE_BENCHMARKS})
     set(CMAKE_BUILD_TYPE "Release")
     add_subdirectory(benchmarks)
 endif()
+
+if (${COMPILE_EXAMPLES})
+    add_subdirectory(examples)
+endif()

README.md

@@ -35,7 +35,13 @@ We provide a small utility script to build the project. We use both CMake and Ni
 
 ## Examples
 
-Some simple examples of usage.
+Some actual real-life inspired examples can be found in the `examples/` directory. You can build them using provided build script:
+
+```bash
+./tools/build.sh --compile-examples
+```
+
+Here we will list some of the simple examples, to show you the power of lazy iteration!
 
 ### Count all even numbers in the iterator
 

examples/CMakeLists.txt

@@ -0,0 +1 @@
+add_subdirectory(aoc)

examples/aoc/CMakeLists.txt

@@ -0,0 +1,3 @@
+add_executable(aoc main.cpp)
+target_compile_features(aoc PRIVATE cxx_std_23)
+target_link_libraries(aoc PRIVATE rusty_iterators)

examples/aoc/input.txt

@@ -0,0 +1,6 @@
+7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9

examples/aoc/main.cpp

@@ -0,0 +1,55 @@
+#include <rusty_iterators/file_iterator.hpp>
+#include <rusty_iterators/iterator.hpp>
+
+#include <cassert>
+#include <iostream>
+#include <sstream>
+#include <string>
+
+using ::rusty_iterators::iterator::FileIterator;
+using ::rusty_iterators::iterator::FIterType;
+using ::rusty_iterators::iterator::LazyIterator;
+
+auto splitByWhitespaceAndCastToInt(std::string str) -> std::vector<int>
+{
+    std::istringstream iss{str};
+    std::vector<int> tokens{};
+    std::string token;
+
+    while (std::getline(iss, token, ' '))
+    {
+        if (!token.empty())
+            tokens.push_back(std::atoi(token.c_str()));
+    }
+    return std::move(tokens);
+}
+
+auto isReportSafe(std::vector<int> vec) -> bool
+{
+    auto signum = (vec.at(1) - vec.at(0)) > 0 ? 1 : -1;
+
+    return LazyIterator{vec}.movingWindow(2).all([&signum](auto x) {
+        auto result     = x.at(1) - x.at(0);
+        auto currSignum = result > 0 ? 1 : -1;
+        auto absResult  = std::abs(result);
+
+        return absResult >= 1 && absResult <= 3 && currSignum == signum;
+    });
+}
+
+/*
+ * An example solution to Advent of Code 2024: day 2, part 1.
+ * https://adventofcode.com/2024/day/2
+ */
+auto main() -> int
+{
+    auto result = FileIterator<FIterType::Lazy>{std::string{"./examples/aoc/input.txt"}}
+                      .map(splitByWhitespaceAndCastToInt)
+                      .filter(isReportSafe)
+                      .count();
+
+    std::cout << "Expected amount of safe reports: 2" << std::endl;
+    std::cout << "Calculated amount of safe reports: " << result << std::endl;
+
+    assert(result == 2);
+}

tools/build.sh

@@ -7,6 +7,7 @@ clean_run=false
 compile_tests=false
 cxx_compiler="g++"
 compile_benchmarks=false
+compile_examples=false
 
 while [[ $# -gt 0 ]]; do
 	case $1 in
@@ -27,6 +28,10 @@ while [[ $# -gt 0 ]]; do
 		compile_benchmarks=true
 		shift
 		;;
+	--compile-examples)
+		compile_examples=true
+		shift
+		;;
 	*)
 		echo "Unknown option $1"
 		exit 1
@@ -41,13 +46,15 @@ echo "C++ Compiler        = ${cxx_compiler}"
 echo "Clean Run           = ${clean_run}"
 echo "Compile Tests       = ${compile_tests}"
 echo "Compile Benchmarks  = ${compile_benchmarks}"
+echo "Compile Examples    = ${compile_examples}"
 echo
 
 cmake \
 	-G Ninja \
 	-D CMAKE_CXX_COMPILER="${cxx_compiler}" \
 	-D COMPILE_TESTS="${compile_tests}" \
 	-D COMPILE_BENCHMARKS="${compile_benchmarks}" \
+	-D COMPILE_EXAMPLES="${compile_examples}" \
 	-S "${repo_root}" \
 	-B build