feat: Adds lesson_04 content

lesson_04/README.md

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+# Lesson 04
+
+## Homework
+
+1. Read CC 12.
+1. Read article entitled [3 Questions That Will Make You A Phenomenal Rubber Duck][article-link]
+1. Complete the [Expression Calculator](#expression-calculator) exercise
+
+## Expression Calculator
+
+For this assignment, you will need to implement the functions and logic required to calculate a mathematical expression. After implementing the `add`, `divide`, and `multiply` functions, you will combine these functions to compute the final result.
+
+1. Update the code in the [ExpressionCalculator.java][calculator-file] file.
+2. To check your work, you can run the application using the first command below and run the tests using the second one.
+```bash
+./gradlew run --console=plain
+./gradlew test
+```
+3. As usual, make sure that you format your code and run the check command before creating your pull request.
+```bash
+./gradlew spotlessApply
+./gradlew check
+```
+4. You must only submit changes to the `ExpressionCalculator.java` file to receive full credit.
+
+[article-link]: https://blog.danslimmon.com/2024/01/18/3-questions-that-will-make-you-a-phenomenal-rubber-duck/
+[calculator-file]: ./expression/expression_app/src/main/java/com/codedifferently/lesson4/ExpressionCalculator.java 

lesson_04/expression/.gitattributes

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+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# Linux start script should use lf
+/gradlew text eol=lf
+
+# These are Windows script files and should use crlf
+*.bat text eol=crlf
+

lesson_04/expression/.gitignore

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+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build

lesson_04/expression/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+ <name>lesson_04</name>
+ <comment>Project quiz created by Buildship.</comment>
+ <projects>
+ </projects>
+ <buildSpec>
+ <buildCommand>
+ <name>org.eclipse.buildship.core.gradleprojectbuilder</name>
+ <arguments>
+ </arguments>
+ </buildCommand>
+ </buildSpec>
+ <natures>
+ <nature>org.eclipse.buildship.core.gradleprojectnature</nature>
+ </natures>
+ <filteredResources>
+ <filter>
+ <id>1708474157606</id>
+ <name></name>
+ <type>30</type>
+ <matcher>
+ <id>org.eclipse.core.resources.regexFilterMatcher</id>
+ <arguments>node_modules|\.git|__CREATED_BY_JAVA_LANGUAGE_SERVER__</arguments>
+ </matcher>
+ </filter>
+ </filteredResources>
+</projectDescription>

lesson_04/expression/.settings/org.eclipse.buildship.core.prefs

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+arguments=--init-script /Users/anthonymays/.local/share/nvim/mason/packages/jdtls/config_mac/org.eclipse.osgi/54/0/.cp/gradle/init/init.gradle
+auto.sync=false
+build.scans.enabled=false
+connection.gradle.distribution=GRADLE_DISTRIBUTION(WRAPPER)
+connection.project.dir=
+eclipse.preferences.version=1
+gradle.user.home=
+java.home=/Library/Java/JavaVirtualMachines/temurin-17.jdk/Contents/Home
+jvm.arguments=
+offline.mode=false
+override.workspace.settings=true
+show.console.view=true
+show.executions.view=true

lesson_04/expression/expression_app/.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+ <classpathentry kind="src" output="bin/main" path="src/main/java">
+ <attributes>
+ <attribute name="gradle_scope" value="main"/>
+ <attribute name="gradle_used_by_scope" value="main,test"/>
+ </attributes>
+ </classpathentry>
+ <classpathentry kind="src" output="bin/test" path="src/test/java">
+ <attributes>
+ <attribute name="gradle_scope" value="test"/>
+ <attribute name="gradle_used_by_scope" value="test"/>
+ <attribute name="test" value="true"/>
+ </attributes>
+ </classpathentry>
+ <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17/"/>
+ <classpathentry kind="con" path="org.eclipse.buildship.core.gradleclasspathcontainer"/>
+ <classpathentry kind="src" path="/instructional-lib">
+ <attributes>
+ <attribute name="without_test_code" value="true"/>
+ </attributes>
+ </classpathentry>
+ <classpathentry kind="output" path="bin/default"/>
+</classpath>

lesson_04/expression/expression_app/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+ <name>expression_app</name>
+ <comment></comment>
+ <projects>
+ </projects>
+ <buildSpec>
+ <buildCommand>
+ <name>org.eclipse.jdt.core.javabuilder</name>
+ <arguments>
+ </arguments>
+ </buildCommand>
+ <buildCommand>
+ <name>org.eclipse.buildship.core.gradleprojectbuilder</name>
+ <arguments>
+ </arguments>
+ </buildCommand>
+ </buildSpec>
+ <natures>
+ <nature>org.eclipse.jdt.core.javanature</nature>
+ <nature>org.eclipse.buildship.core.gradleprojectnature</nature>
+ </natures>
+ <filteredResources>
+ <filter>
+ <id>1</id>
+ <name></name>
+ <type>30</type>
+ <matcher>
+ <id>org.eclipse.core.resources.regexFilterMatcher</id>
+ <arguments>node_modules|\.git|__CREATED_BY_JAVA_LANGUAGE_SERVER__</arguments>
+ </matcher>
+ </filter>
+ </filteredResources>
+</projectDescription>

lesson_04/expression/expression_app/.settings/org.eclipse.buildship.core.prefs

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+connection.project.dir=..
+eclipse.preferences.version=1

lesson_04/expression/expression_app/.settings/org.eclipse.jdt.core.prefs

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+eclipse.preferences.version=1
+org.eclipse.jdt.core.classpath.outputOverlappingAnotherSource=ignore
+org.eclipse.jdt.core.compiler.annotation.missingNonNullByDefaultAnnotation=ignore
+org.eclipse.jdt.core.compiler.annotation.nonnull=org.eclipse.jdt.annotation.NonNull
+org.eclipse.jdt.core.compiler.annotation.nonnullbydefault=org.eclipse.jdt.annotation.NonNullByDefault
+org.eclipse.jdt.core.compiler.annotation.nullable=org.eclipse.jdt.annotation.Nullable
+org.eclipse.jdt.core.compiler.annotation.nullanalysis=disabled
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=17
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=17
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.problem.nullAnnotationInferenceConflict=error
+org.eclipse.jdt.core.compiler.problem.nullReference=warning
+org.eclipse.jdt.core.compiler.problem.nullSpecViolation=error
+org.eclipse.jdt.core.compiler.problem.potentialNullReference=ignore
+org.eclipse.jdt.core.compiler.problem.syntacticNullAnalysisForFields=disabled
+org.eclipse.jdt.core.compiler.source=17

lesson_04/expression/expression_app/build.gradle.kts

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+plugins {
+ // Apply the application plugin to add support for building a CLI application in Java.
+ application
+ eclipse
+ id("com.diffplug.spotless") version "6.25.0"
+ id("org.springframework.boot") version "3.2.2"
+}
+
+apply(plugin = "io.spring.dependency-management")
+
+repositories {
+ // Use Maven Central for resolving dependencies.
+ mavenCentral()
+}
+
+dependencies {
+ // Use JUnit Jupiter for testing.
+ testImplementation("com.codedifferently.instructional:instructional-lib")
+ testImplementation("org.junit.jupiter:junit-jupiter:5.9.1")
+ testImplementation("org.springframework.boot:spring-boot-starter-test")
+ testImplementation("org.assertj:assertj-core:3.25.1")
+ testImplementation("at.favre.lib:bcrypt:0.10.2")
+
+ // This dependency is used by the application.
+ implementation("com.codedifferently.instructional:instructional-lib")
+ implementation("com.google.guava:guava:31.1-jre")
+ implementation("org.projectlombok:lombok:1.18.30")
+ implementation("org.springframework.boot:spring-boot-starter")
+}
+
+application {
+ // Define the main class for the application.
+ mainClass.set("com.codedifferently.lesson4.Lesson4")
+}
+
+tasks.named<JavaExec>("run") {
+ standardInput = System.`in`
+}
+
+tasks.named<Test>("test") {
+ // Use JUnit Platform for unit tests.
+ useJUnitPlatform()
+}
+
+
+configure<com.diffplug.gradle.spotless.SpotlessExtension> {
+
+ format("misc", {
+ // define the files to apply `misc` to
+ target("*.gradle", ".gitattributes", ".gitignore")
+
+ // define the steps to apply to those files
+ trimTrailingWhitespace()
+ indentWithTabs() // or spaces. Takes an integer argument if you don't like 4
+ endWithNewline()
+ })
+
+ java {
+ // don't need to set target, it is inferred from java
+
+ // apply a specific flavor of google-java-format
+ googleJavaFormat()
+ // fix formatting of type annotations
+ formatAnnotations()
+ }
+}

lesson_04/expression/expression_app/src/main/java/com/codedifferently/lesson4/ExpressionCalculator.java

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+package com.codedifferently.lesson4;
+
+public class ExpressionCalculator {
+ /**
+ * Returns the calculation of ((a + b) * c) / d^e
+ *
+ * @param a
+ * @param b
+ * @return
+ */
+ public double calculate(double a, double b, double c, double d, double e) {
+ // Implement your code here to return the correct value.
+ return 0d;
+ }
+
+ public double pow(double base, double exponent) {
+ return Math.pow(base, exponent);
+ }
+}

lesson_04/expression/expression_app/src/main/java/com/codedifferently/lesson4/Lesson4.java

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+package com.codedifferently.lesson4;
+
+import java.util.Scanner;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@SpringBootApplication(scanBasePackages = "com.codedifferently")
+public class Lesson4 implements CommandLineRunner {
+
+ public static void main(String[] args) {
+ // To test, use `./gradlew run --console=plain`
+ var application = new SpringApplication(Lesson4.class);
+ application.run(args);
+ }
+
+ public void run(String... args) {
+ // Use Scanner to get input from the user.
+ var scanner = new Scanner(System.in);
+
+ System.out.print("\nEnter a value for variable 'a': ");
+ int a = scanner.nextInt();
+
+ System.out.print("Enter a value for variable 'b': ");
+ int b = scanner.nextInt();
+
+ System.out.print("Enter a value for variable 'c': ");
+ int c = scanner.nextInt();
+
+ System.out.print("Enter a value for variable 'd': ");
+ int d = scanner.nextInt();
+
+ System.out.print("Enter a value for variable 'e': ");
+ int e = scanner.nextInt();
+
+ // Close the scanner to avoid memory leaks.
+ scanner.close();
+
+ System.out.println(
+ String.format("\nNow computing the value of ((%s + %s) * %s) / %s^%s", a, b, c, d, e));
+
+ var calculator = new ExpressionCalculator();
+ double result = calculator.calculate(a, b, c, d, e);
+
+ System.out.println(String.format("The result is: %s", result));
+ }
+}

lesson_04/expression/expression_app/src/test/java/com/codedifferently/lesson4/Lesson4Test.java

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+package com.codedifferently.lesson4;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.lang.reflect.Method;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class Lesson4Test {
+
+ private ExpressionCalculator calculator;
+
+ @BeforeEach
+ void setUp() {
+ calculator = new ExpressionCalculator();
+ }
+
+ @Test
+ void testCalculate() {
+ // Arrange
+ var a = 1;
+ var b = 2;
+ var c = 3;
+ var d = 4;
+ var e = 5;
+ var expected = ((a + b) * c) / Math.pow(d, e);
+
+ // Act
+ double actual = calculator.calculate(a, b, c, d, e);
+
+ // Assert
+ assertThat(actual).isEqualTo(expected);
+ }
+
+ @Test
+ void testAdd_works() throws Exception {
+ // Arrange
+ Method method = calculator.getClass().getDeclaredMethod("add", double.class, double.class);
+
+ // Act
+ var result = (double) method.invoke(calculator, 1, 2);
+
+ // Assert
+ assertThat(result).isEqualTo(3);
+ }
+
+ @Test
+ void testMultipy_works() throws Exception {
+ // Arrange
+ Method method = calculator.getClass().getDeclaredMethod("multiply", double.class, double.class);
+
+ // Act
+ var result = (double) method.invoke(calculator, 1, 2);
+
+ // Assert
+ assertThat(result).isEqualTo(2);
+ }
+
+ @Test
+ void testDivide_works() throws Exception {
+ // Arrange
+ Method method = calculator.getClass().getDeclaredMethod("divide", double.class, double.class);
+
+ // Act
+ var result = (double) method.invoke(calculator, 1, 2);
+
+ // Assert
+ assertThat(result).isEqualTo(0.5d);
+ }
+
+ @Test
+ void testPow_works() throws Exception {
+ // Arrange
+ Method method = calculator.getClass().getDeclaredMethod("pow", double.class, double.class);
+
+ // Act
+ var result = (double) method.invoke(calculator, 2, 3);
+
+ // Assert
+ assertThat(result).isEqualTo(8);
+ }
+}

lesson_04/expression/gradle/wrapper/gradle-wrapper.properties

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+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.0.2-bin.zip
+networkTimeout=10000
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists