Add Composition Example

Java/Algorithm/FindTheOccurenceOfCharacter.java

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+import java.util.HashMap;
+import java.util.Map;
+
+//Given a string, count the frequency/occurence of each Character
+public class FindTheOccurenceOfCharacter {
+    static HashMap<Character, Integer> getOccurence(String inputString) {
+        HashMap<Character, Integer> characterFrequencyMap
+        = new HashMap<Character, Integer>();
+
+
+    char[] inputArray = inputString.toLowerCase().toCharArray();
+
+    for (char character : inputArray) {
+        if (characterFrequencyMap.containsKey(character)) {
+            characterFrequencyMap.put(character, characterFrequencyMap.get(character) + 1);
+        }
+        else {
+            characterFrequencyMap.put(character, 1);
+        }
+    }
+
+    return characterFrequencyMap;
+    }
+
+    static void  printOccurence(HashMap<Character, Integer> map){
+        for (Map.Entry<Character, Integer> value: map.entrySet()) {
+            System.out.println(value.getKey() + "->" + value.getValue());
+        }
+    }
+
+    public static void main(String[] args) {
+        String inputString = "Test";
+
+        HashMap<Character, Integer> map = getOccurence(inputString);
+
+        printOccurence(map);
+
+    }
+}

Java/OOP/Composition/CompositionStudentExample/Student.java

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+package CompositionStudentExample;
+
+import java.util.List;
+
+public class Student {
+    private String name;
+    private int age;
+    private List<Subject> subjects; //Student has a list of Subjects
+
+    public Student(String name, int age, List<Subject> subjects) {
+        this.setName(name);
+        this.setAge(age);
+        this.setSubjects(subjects);
+    }
+
+    public List<Subject> getSubjects() {
+        return subjects;
+    }
+
+    public void setSubjects(List<Subject> subjects) {
+        this.subjects = subjects;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public void printStudentDetails() {
+        System.out.println("Student " + this.name + " has taken the sujects ");
+        for (int i = 0; i < subjects.size(); i++) {
+            System.out.println(subjects.get(i).getName());
+        }
+    }
+
+}

Java/OOP/Composition/CompositionStudentExample/Subject.java

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+package CompositionStudentExample;
+
+public class Subject {
+    private String code;
+    private String name;
+
+    public Subject(String code, String name) {
+        this.setCode(code);
+        this.setName(name);
+    }
+
+    public String getCode() {
+        return code;
+    }
+
+    public void setCode(String code) {
+        this.code = code;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

Java/OOP/Composition/CompositionStudentExample/Test.java

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+package CompositionStudentExample;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Test {
+    public static void main(String[] args) {
+        Subject english = new Subject("ENG101", "English");
+        Subject mathematics = new Subject("MATH101", "Mathematics");
+        Subject science = new Subject("SCI01", "Science");
+
+        Subject economics = new Subject("ECO101", "Economics");
+        Subject businessStudies = new Subject("BUS01", "Business Studies");
+        Subject accounts = new Subject("ACC101", "Accounts");
+
+        List<Subject> subjectsForScienceStudent = new ArrayList<Subject>();
+        subjectsForScienceStudent.add(english);
+        subjectsForScienceStudent.add(mathematics);
+        subjectsForScienceStudent.add(science);
+
+        List<Subject> subjectsForCommerceStudent = new ArrayList<Subject>();
+        subjectsForCommerceStudent.add(english);
+        subjectsForCommerceStudent.add(economics);
+        subjectsForCommerceStudent.add(businessStudies);
+        subjectsForCommerceStudent.add(accounts);
+
+        Student commerceStudent = new Student("Ravi",18, subjectsForCommerceStudent);
+        Student scienceStudent = new Student("Chavi",19, subjectsForScienceStudent);
+
+        commerceStudent.printStudentDetails();
+        scienceStudent.printStudentDetails();
+    }
+
+}