程序清单9.1-9.3

单独编译

file/coordin.h

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+#ifndef COORDIN_H_
+#define COORDIN_H_
+
+struct polar
+{
+	double distance;
+	double angle;
+};
+
+struct rect
+{
+	double x;
+	double y;
+};
+
+polar rect_to_polar(rect xypos);
+void show_polar(polar dapos);
+
+#endif

file/file1.cpp

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+#include <iostream>
+#include "coordin.h"
+using namespace std;
+int main()
+{
+	rect rplace;
+	polar pplace;
+	cout << "Enter the x and y values: ";
+	while (cin >> rplace.x >> rplace.y)
+	{
+		pplace = rect_to_polar(rplace);
+		show_polar(pplace);
+		cout << "Next two numbers (q to quit): ";
+	}
+	cout << "Bye!" << endl;
+	return 0;
+}

file/file2.cpp

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+#include <iostream>
+#include <cmath>
+#include "coordin.h"
+using namespace std;
+polar rect_to_polar(rect xypos)
+{
+	polar answer;
+	answer.distance = sqrt(xypos.x*xypos.x + xypos.y*xypos.y);
+	answer.angle = atan2(xypos.y, xypos.x);
+	return answer;
+}
+void show_polar(polar dapos)
+{
+	const double Rad_to_deg = 57.29577951;
+	cout << "distance = " << dapos.distance;
+	cout << ", angle = " << dapos.angle*Rad_to_deg;
+	cout << " degrees" << endl;
+}