Add sample with custom types and more complex logic, reading and writing data

src/sample_3.cpp

+#include <iostream>
+#include "sample_3.h"
+
+
+void city::copy_repaint(city::House torepaint) {
+	torepaint.color = black;
+}
+
+void city::copy_free_repaint(city::House &torepaint) {
+	torepaint.color = black;
+}
+
+void city::describe_house(city::House &house) {
+	std::cout << "The resident " << house.owner;
+	std::cout << " is currently living in their ";
+	switch (house.color)
+	{
+	case red:
+		std::cout << "red";
+		break;
+	case green:
+		std::cout << "green";
+		break;
+	case blue:
+		std::cout << "blue";
+		break;
+	case black:
+		std::cout << "black";
+		break;
+	case white:
+		std::cout << "white";
+		break;
+	default:
+		std::cout << "mystey-colored";
+		break;
+	}
+	std::cout << " house at number " << house.number << std::endl;
+}
+
+int main(int argc, char** argv) {
+	using std::string;
+	using std::cout;
+	using std::cin;
+	using std::endl;
+	using namespace city;
+
+	// Declare a variable to hold the name of the user
+	string owner;
+
+	// Write out static text
+	cout << "Dear new resident of the city. Please tell us your name:" << endl;
+
+	// An infinite loop
+	while (1) {
+		// Read in a string
+		cin >> owner;
+
+		// Check if the name has at least 3 characters
+		if (owner.length() < 3) {
+			// Print out hint
+			cout << "Your name is suspiciously short. Please enter at least 3 characters" << endl;
+			// Skip to next run of loop
+			continue;
+		}
+		else {
+			// Write out a mix of a static string and the string previously read in
+			cout << "So your name is " << owner << "." << endl;
+
+			// Let us break free of this infinite loop
+			break;
+		}
+	}
+
+
+	// Let's ask the user for a color of the house
+	cout << "Which color should your house have? (r|g|b|w)" << endl;
+
+	HouseColor houseColor;
+	char color;
+	while (1) {
+		// Read one character from the input
+		cin >> color;
+		// Discard the rest of the line
+		cin.ignore();
+
+		// Add a variable to keep track of an error
+		bool unknown_color = false;
+
+		// Handle different cases of the entered color
+		switch (color) {
+		case 'r':
+			houseColor = red;
+			break;
+		case 'g':
+			houseColor = green;
+			break;
+		case 'b':
+			houseColor = blue;
+			break;
+		case 'w':
+			houseColor = white;
+			break;
+		default:
+			unknown_color = true;
+			break;
+		}
+
+		// Deal with an unknown color
+		if (unknown_color) {
+			cout << "The color you chose was not known. Please choose one out of r,g,b,w" << endl;
+			// Retry
+			continue;
+		}
+		else {
+			cout << "The color you chose was " << color << ". Your house will be painted in this color." << endl;
+			// End loop
+			break;
+		}
+	}
+
+	cout << "Do you have a favorite house number?" << endl;
+
+	// Define a variable for the house number
+	int32_t house_number;
+
+	// Another infinite loop for the reading of the house number
+	while (1) {
+		// Read the number
+		cin >> house_number;
+
+		if (house_number <= 0) {
+			cout << "Oh no! Your favorite house number should certainly be positive. Please consider this again." << endl;
+			// Retry
+			continue;
+		}
+		else {
+			cout << "Oh, so your house will have the number " << house_number << " just for you." << endl;
+			// Stop the trying loop
+			break;
+		}
+	}
+
+
+	// Declare a house of custom type and assign its member fields.
+	House designed_house;
+	designed_house.color = houseColor;
+	designed_house.number = house_number;
+	designed_house.owner = owner;
+
+	std::cout << "Let us summarize your registration:" << endl;
+	describe_house(designed_house);
+
+	std::cout << "Let us summarize your registration:" << endl;
+	describe_house(designed_house);
+
+	std::cout << "We will now try to repaint your house black:" << endl;
+	copy_repaint(designed_house);
+	describe_house(designed_house);
+
+	std::cout << "Let us try it again a little differently:" << endl;
+	copy_free_repaint(designed_house);
+	describe_house(designed_house);
+
+
+	return 0;
+}
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src/sample_3.h

+#ifndef __SAMPLE_3_H__
+#define __SAMPLE_3_H__
+
+#include <string>
+
+namespace city {
+
+	// A custom type with a fixed number of permitted values
+	enum HouseColor {
+		red,
+		blue,
+		green,
+		white,
+		black
+	};
+
+	// A custom type with data fields
+	struct House {
+		// Our custom color
+		HouseColor color;
+		// A house number
+		uint32_t number;
+		// The name of the owner
+		std::string owner;
+	};
+
+	// A function to illustrate call by value
+	void copy_repaint(House torepaint);
+
+	// A function to illustrate call by referene
+	void copy_free_repaint(House &torepaint);
+
+	// A function to print out a description of the house
+	void describe_house(House &house);
+};
+
+#endif
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