added drill16 for chapter13

Author: trapperdot00

Chapter13/README.md

@@ -49,3 +49,6 @@ Define a variable of type `Person`, initialize it with "Goofy" and 63, and write
 
 ## [Drill 15](drill/15)
 Define an input (`>>`) and an output (`<<`) operator for `Person`; read in a `Person` from the keyboard (`cin`) and write it out to the screen (`cout`).
+
+## [Drill 16](drill/16)
+Give `Person` a constructor initializing `name` and `age`.

Chapter13/drill/16/Person.cpp

@@ -0,0 +1,12 @@
+#include "Person.h"
+
+std::istream& operator>>(std::istream& is, Person& rhs) {
+	Person p;
+	if (is >> p.name >> p.age)
+		rhs = p;
+	return is;
+}
+
+std::ostream& operator<<(std::ostream& os, const Person& rhs) {
+	return os << rhs.name << ' ' << rhs.age;
+}

Chapter13/drill/16/Person.h

@@ -0,0 +1,18 @@
+#ifndef PERSON_H
+#define PERSON_H
+
+#include <string>
+#include <iostream>
+
+struct Person {
+	Person() {}
+	Person(const std::string& s, int i)
+		: name{s}, age{i} {}
+	std::string name;
+	int age;
+};
+
+std::istream& operator>>(std::istream&, Person&);
+std::ostream& operator<<(std::ostream&, const Person&);
+
+#endif

Chapter13/drill/16/main.cpp

@@ -0,0 +1,10 @@
+#include "Person.h"
+
+#include <iostream>
+
+int main() {
+	Person p;
+	std::cout << "Enter person: ";
+	if (std::cin >> p)
+		std::cout << p << '\n';
+}