c++ solutions for ques 6, 7, 8, 9, 10, 11, 12 for chap 17

c++/Chapter 17/Question17_10.cpp

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+#include <iostream>
+#include <fstream>
+#include <vector>
+#include <string>
+#include <memory>
+
+using namespace std;
+
+/** Attribute class */
+class Attribute {
+
+private:
+  string tag;
+  string value;
+
+public:
+  Attribute(); // def cons
+  Attribute(string, string); // cons
+  ~Attribute(); // destructor
+
+  /** getters */
+  string get_tag() { return tag; }
+
+  string get_value() { return value; }
+
+  /** other functions */
+  string get_tag_code();
+};
+
+/** Attribute constructor and functions */
+Attribute::Attribute() { }
+
+Attribute::Attribute(string tag, string value) {
+  this->tag = tag;
+  this->value = value;
+}
+
+Attribute::~Attribute() { }
+
+string Attribute::get_tag_code() {
+  if (this->tag == "family")
+			return "1";
+		else if (this->tag == "person")
+			return "2";
+		else if (this->tag == "firstname")
+			return "3";
+		else if (this->tag == "lastname")
+			return "4";
+		else if (this->tag == "state")
+			return "5";
+		else
+			return "--";
+}
+
+/** Element Class */
+class Element {
+
+private:
+  string name;
+  string value;
+  vector<Attribute> attributes;
+  vector<Element> children;
+
+public:
+  Element(); // def cons
+  Element(string); // cons 1
+  Element(string, string); // cons 2
+
+  ~Element(); // des
+
+  /** getters */
+  string get_name() { return name; }
+
+  string get_value() { return value; }
+
+  vector<Attribute> get_attributes() { return attributes; }
+
+  vector<Element> get_children() { return children; }
+
+  /** other functions */
+  string get_name_code();
+  void insert_Att(Attribute att) {
+    attributes.push_back(att);
+  }
+  void insert_Elem(Element elem) {
+    children.push_back(elem);
+  }
+};
+
+/** Element constructor and functions */
+Element::Element() { }
+
+Element::Element(string name) {
+  this->name = name;
+}
+
+Element::Element(string name, string value) {
+  this->name = name;
+  this->value = value;
+}
+
+Element::~Element() { }
+
+string Element::get_name_code() {
+  if (this->name == "family")
+			return "1";
+	else if (this->name == "person")
+		return "2";
+	else if (this->name == "firstname")
+		return "3";
+	else if (this->name == "lastname")
+		return "4";
+	else if (this->name == "state")
+		return "5";
+	else
+		return "--";
+}
+
+/* Function declarations */
+void encode(Element root, string& str);
+void encode(Attribute attr, string& str);
+void encode(string str1, string& str2);
+string encode_xml_to_str(Element& root);
+
+/** Common functions definitions */
+
+void encode(Element root, string& str) {
+
+  /* Append the root's name code */
+  encode(root.get_name_code(), str);
+
+  /* Recurse over the attributes */
+  for (auto& attr : root.get_attributes()) {
+    encode(attr, str);
+  }
+
+  encode("0", str); // this is the end of the element hence append as '0'
+
+  /* Recurse over the child Elements */
+  if (root.get_value() != "") {
+    encode(root.get_value(), str);
+  }
+  else {
+    for (auto& child : root.get_children()) {
+      encode(child, str);
+    }
+  }
+  encode("0", str);
+}
+
+void encode(Attribute attr, string& str) {
+  encode(attr.get_tag_code(), str);
+  encode(attr.get_value(), str);
+}
+
+void encode(string str1, string& str2) {
+  str2 += str1 + " ";
+}
+
+string encode_xml_to_str(Element& root) {
+  string str = "";
+  encode(root, str);
+  return str;
+}
+
+/****** MAIN FUNCTION ******/
+
+int main() {
+
+  /** Forming the XML */
+  Element root("family");
+  Attribute a1("lastname", "McDowell");
+  Attribute a2("state", "CA");
+  root.insert_Att(a1);
+  root.insert_Att(a2);
+
+  Element child("person", "Some Message");
+  Attribute a3("firstname", "Gayle");
+  child.insert_Att(a3);
+  root.insert_Elem(child);
+
+  /** Calling the encode xml function */
+  string res = encode_xml_to_str(root);
+
+  cout << res << endl;
+
+  return 0;
+}
+
+/*
+
+Commands to run
+----------------
+
+g++ -std=c++11 Question17_10.cpp -o Question17_10
+./Question17_10
+
+*/

c++/Chapter 17/Question17_11.cpp

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+#include <iostream>
+#include <stdlib.h>
+
+using namespace std;
+
+#define NUMBER_5 5
+
+int rand5();
+int rand7();
+int rand7_alternate();
+
+int rand5() {
+  return (rand() % NUMBER_5);
+}
+
+int rand7() {
+  while (true) {
+    int num = 5 * rand5() + rand5();
+    if (num < 21) {
+      return num % 7;
+    }
+  }
+}
+
+int rand7_alternate() {
+  while (true) {
+    int r1 = 2 * rand5();
+    int r2 = rand5();
+    if (r2 != 4) {
+      int rand1 = r2 % 2;
+      int num = r1 + rand1;
+      if (num < 7)
+        return num;
+    }
+  }
+}
+
+int main() {
+
+  cout << "\n---------------  Using Method rand7() ---------------\n" << endl;
+  for (int i=0; i<10; i++) {
+    cout << rand7() << ", ";
+  }
+  cout << endl;
+
+  cout << "\n---------------  Using Method rand7_alternate() ---------------\n" << endl;
+  for (int i=0; i<10; i++) {
+    cout << rand7_alternate() << ", ";
+  }
+  cout << endl;
+
+  return 0;
+}
+
+/*
+
+Commands to run
+----------------
+
+g++ -std=c++11 Question17_11.cpp -o Question17_11
+./Question17_11
+
+*/

c++/Chapter 17/Question17_12.cpp

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+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+void pair_sum(vector<int>, int);
+
+void pair_sum(vector<int> a, int target_sum) {
+
+  /** Sort the vector */
+  sort(a.begin(), a.end());
+
+  int left = 0, right = a.size()-1, curr_sum = 0;
+
+  while (left < right) {
+      curr_sum = a[left] + a[right];
+      if (curr_sum == target_sum) {
+        cout << "Found Pair : {" << a[left] << ", " << a[right] << "}" << endl;
+        left++;
+        right--;
+      }
+      else if (curr_sum > target_sum) {
+        right--;
+      }
+      else {
+        left++;
+      }
+  }
+}
+
+int main() {
+
+  int arr[] = {9, 3, 6, 5, 7, -1, 13, 14, -2, 12, 0};
+  int size = sizeof(arr)/sizeof(*arr);
+  vector<int> ar(arr, arr+size);
+  int target_sum = 12;
+
+  pair_sum(ar, target_sum);
+}
+
+/*
+
+Commands to run
+----------------
+
+g++ -std=c++11 Question17_12.cpp -o Question17_12
+./Question17_12
+
+*/