more

1 files changed, 74 insertions, 0 deletions

diff --git a/7p29.cpp b/7p29.cpp
new file mode 100644
index 0000000..44582bb
--- /dev/null
+++ b/7p29.cpp
@@ -0,0 +1,74 @@
+#include <iostream>
+
+/*
+ *
+ * 7.29
+ *
+ *
+ */
+
+class Screen {
+public:
+	typedef std::string::size_type Pos;
+	Screen() = default;
+	Screen(Pos ht, Pos wd): Height(ht), Width(wd), Contents(ht * wd, ' ') { }
+	Screen(Pos ht, Pos wd, char c): Height(ht), Width(wd), Contents(ht * wd, c) { }
+	char get() const { return Contents[Cursor]; }
+	inline char get(Pos ht, Pos wd) const;
+	Screen move(Pos r, Pos c);
+	inline Screen set(char c);
+	inline Screen set(Pos r, Pos col, char ch);
+	Screen display(std::ostream &os) { do_display(os); return *this; }
+	const Screen display(std::ostream &os) const { do_display(os); return *this; }
+	void printheight(Pos Height);
+private:
+	void do_display(std::ostream &os) const {os << Contents;}
+	Pos Cursor = 0;
+	Pos Height = 0;
+	Pos Width = 0;
+	std::string Contents;
+};
+
+inline Screen Screen::set(char c)
+{
+	Contents[Cursor] = c; // set the new value at the current cursor location
+	return *this;
+	// return this object as an lvalue
+}
+
+inline Screen Screen::set(Pos r, Pos col, char ch)
+{
+	Contents[r*Width + col] = ch; // set specified location to given value
+	return *this;
+	// return this object as an lvalue
+}
+
+inline Screen Screen::move(Pos r, Pos c)
+{
+	Pos row = r * Width; // compute the row location
+	Cursor = row + c;
+	// move cursor to the column within that row
+	return *this;
+	// return this object as an lvalue
+}
+
+char Screen::get(Pos r, Pos c) const // declared as inline in the class
+{
+	Pos row = r * Width;
+	// compute row location
+	return Contents[row + c]; // return character at the given column
+}
+
+void printheight(Screen::Pos Height) {
+	std::cout << Height;
+}
+
+int main () {
+
+	Screen myScreen(5, 5, 'X');
+	myScreen.move(4,0).set('#').display(std::cout);
+	std::cout << "\n";
+	myScreen.display(std::cout);
+	std::cout << "\n";
+	return 0;
+}