11-1
//headfile #pragma once #ifndef VECTOR_H_ #define VECTOR_H_ #include <iostream> namespace VECTOR { class Vector { public: enum Mode { RECT, POL }; //RECT指平面坐标，POL指极坐标 private: double x; double y; double mag; double ang; Mode mode; void set_mag(); void set_ang(); void set_x(); void set_y(); public: Vector(); Vector(double n1, double n2, Mode form = RECT); void reset(double n1, double n2, Mode form = RECT); ~Vector(); //内联函数 double xval() const { return x; } double yval() const { return y; } double magval() const { return mag; } double angval() const { return ang; } void polar_mode(); void rect_mode(); //操作符重载 Vector operator+(const Vector & b) const; Vector operator-(const Vector & b) const; Vector operator-() const; Vector operator*(double n) const; //友元函数 friend Vector operator*(double n, const Vector & a); friend std::ostream & operator << (std::ostream & os, const Vector & v); }; } #endif // !VECTOR_H_ //realize file #include "pch.h" #include <cmath> #include "vector.h" using std::sqrt; using std::sin; using std::cos; using std::atan; using std::atan2; using std::cout; namespace VECTOR { const double Rad_to_deg = 45.0 / atan(1.0); //约为57.2958 //私有函数 void Vector::set_mag() { mag = sqrt(x * x + y * y); } void Vector::set_ang() { if (x == 0.0 && y == 0.0) ang = 0.0; else ang = atan2(y, x); } void Vector::set_x() { x = mag * cos(ang); } void Vector::set_y() { y = mag * sin(ang); } //公有函数 Vector::Vector() { x = y = mag = ang = 0.0; mode = RECT; } Vector::Vector(double n1, double n2, Mode form) { mode = form; if (form == RECT) { x = n1; y = n2; set_mag(); set_ang(); } else if (form == POL) { mag = n1; ang = n2 / Rad_to_deg; set_x(); set_y(); } else { cout << "Incorrect 3rd argument to Vector() -- "; cout << "Vector set to 0 "; x = y = mag = ang = 0.0; mode = RECT; } } void Vector::reset(double n1, double n2, Mode form) { mode = form; if (form == RECT) { x = n1; y = n2; set_mag(); set_ang(); } else if (form == POL) { mag = n1; ang = n2 / Rad_to_deg; set_x(); set_y(); } else { cout << "Incorrect 3rd argument to Vector() -- "; cout << "Vector set to 0 "; x = y = mag = ang = 0.0; mode = RECT; } } Vector::~Vector() { } void Vector::polar_mode() { mode = POL; } void Vector::rect_mode() { mode = RECT; } Vector Vector::operator+(const Vector & b) const { return Vector(x + b.x, y + b.y); } Vector Vector::operator-(const Vector & b) const { return Vector(x - b.x, y - b.y); } Vector Vector::operator-() const { return Vector(-x, -y); } Vector Vector::operator*(double n) const { return Vector(n * x, n * y); } Vector operator*(double n, const Vector & a) { return a * n; } std::ostream & operator<<(std::ostream & os, const Vector & v) { //这里的operator<<()是友元函数，在名称空间中，但不在类定义中 //使用要使用Vector::RECT if (v.mode == Vector::RECT) os << "(x,y) = (" << v.x << ", " << v.y << ")"; else if (v.mode == Vector::POL) os << "(m,a) = (" << v.mag << ", " << v.ang*Rad_to_deg << ")"; else os << "Vector object mode is invalid"; return os; } } //main file #include "pch.h" #include <iostream> #include <string> #include <cstring> #include <cctype> #include <cstdlib> #include <ctime> #include <fstream> #include "vector.h" using namespace std; int main(void) { using VECTOR::Vector; srand(time(0)); ofstream outFile; outFile.open("random walker.txt"); double direction; Vector step; Vector result(0.0, 0.0); unsigned long steps = 0; double target; double dstep; cout << "Enter terget distance (q to quit): "; while (cin >> target) { cout << "Enter step length: "; if (!(cin >> dstep)) break; //写入文件中 outFile << "Target Distance: " << target << ", Step Size: " << dstep << endl; outFile << 0 << ": " << result << endl; while (result.magval() < target) { direction = rand() % 360; step.reset(dstep, direction, Vector::POL); result = result + step; steps++; outFile << steps << ": " << result << endl; } //显示在屏幕上 cout << "After " << steps << " steps, the subject " "has the following location: "; cout << result << endl; result.polar_mode(); cout << " or " << result << endl; cout << "Average outward distance per step = " << result.magval() / steps << endl; //写入文件中 outFile << "After " << steps << " steps, the subject " "has the following location: "; outFile << result << endl; result.polar_mode(); outFile << " or " << result << endl; outFile << "Average outward distance per step = " << result.magval() / steps << endl; steps = 0; result.reset(0.0, 0.0); cout << "Enter target distance (q to quit): "; } cout << "Bye! "; cin.clear(); while (cin.get() != ' ') continue; return 0; }
11-2
double Vector::magval() { return sqrt(x * x + y * y); } double Vector::angval() { return atan2(y, x); } //将11-1中magval和angval不在头文件中直接定义，放到实现文件中重新定义实现文件.
11-3
#include <iostream> #include <cstdlib> #include <ctime> #include "vect.h" int main() { using namespace std; using VECTOR::Vector; srand(time(0));//设置随机数种子 double direction;//方向 Vector step;//新的一步 Vector result(0,0);//当前位置 int steps = 0;//步数 double target;//目标距离 double dstep;//每一步的距离 cout << "Enter target distance (q to quit): "; while (cin >> target) { cout << "Enter step length: "; if (!(cin >> dstep)) { break; } cout << "Target Distance: " << target <<", Step Size: " << dstep <<endl; int num = 0;//测试次数 cout << "Enter Test Times: ";//输入测试次数 if (!(cin>> num) || num < 0) { break; } int maxSteps = 0; int minSteps = 0; int totalSteps = 0; for (int i = 0; i < num; ++i) { //cout << 0 << ": " << result << endl; while(result.magval() < target) { //离起点的距离还没达到目标距离，就要继续执行 direction = rand() % 360;//随机一个方向，角度 step.reset(dstep, direction, Vector::POL);//当前的一步 result = result + step;//当前的实际位置 steps++;//计数 // cout << steps << ": " << result << endl;略去中间过程 } cout << " Times #" << i+1 << ": "; cout << "After " << steps << " steps, the subject has the following location: "; cout << result <<endl; result.polar_mode(); cout << " or " << result << endl; cout << "Average outward distance per step = " << result.magval() / steps << endl; if (i == 0) { totalSteps = minSteps = maxSteps = steps; } else { totalSteps += steps; if (minSteps > steps) minSteps = steps; if (maxSteps < steps) maxSteps = steps; } steps = 0; result.reset(0, 0); } cout << " Test Times: " << num << " average steps: "<< totalSteps / num << endl; cout << "Max steps: " << maxSteps << " Min steps: " << minSteps << endl; cout << "Enter target distance (q to quit): "; } cout << "Bye! "; cin.clear(); while (cin.get() != ' ') { continue; } return 0; } //类定义和实现文件不改动，修改主函数如下即可
11-4
//头文件 #ifndef MYTIME3_H_ #define MYTIME3_H_ #include <iostream> class Time { private: int hours; int minutes; public: Time(); Time(int h, int m = 0); void AddMin(int m); void AddHr(int h); void reset(int h = 0, int m = 0); friend Time operator+(const Time & a, const Time & b); friend Time operator-(const Time & a, const Time & b); friend Time operator*(const Time & a, double b); friend Time operator*(double m, const Time & t) { return t * m; } //内联函数 friend std::ostream & operator << (std::ostream & os, const Time & t); }; #endif //类实现文件 #include "U11p4mytime.h" Time::Time() { hours = minutes = 0; } Time::Time(int h, int m) { hours = h; minutes = m; } void Time::AddMin(int m) { minutes += m; hours += minutes / 60; minutes %= 60; } void Time::AddHr(int h) { hours += h; } void Time::reset(int h, int m) { hours = h; minutes = m; } Time operator+(const Time & a, const Time & b) { Time sum; sum.minutes = a.minutes + b.minutes; sum.hours = a.hours + b.hours + sum.minutes / 60; sum.minutes %= 60; return sum; } Time operator-(const Time & a, const Time & b) { Time diff; int tot1, tot2; tot1 = b.minutes + 60 * b.hours; tot2 = a.minutes + 60 * a.hours; diff.minutes = (tot2 - tot1) % 60; diff.hours = (tot2 - tot1) / 60; return diff; } Time operator*(const Time & a, double b) { Time result; int total; total = a.hours * 60 * b + a.minutes * b; result.hours = total / 60; result.minutes = total % 60; return result; } std::ostream & operator<< (std::ostream & os, const Time & t) { os << t.hours << " hours, " << t.minutes << " minutes"; return os; } //主程序文件 #include <iostream> #include "U11p4mytime.h" int main() { using std::cout; using std::endl; Time aida(3, 35); Time tosca(2, 48); Time temp; cout << "Aida and Tosca: "; cout << aida << "; " << tosca << endl; temp = aida + tosca;//operator+() cout << "Aida + Tosca: " << temp << endl; temp = aida - tosca;//operator-() cout << "Aida - Tosca: " << temp << endl; temp = aida * 1.17; cout << "Aida * 1.17: " << temp << endl; cout << "10.0 * Aida: " << 10.0 * tosca << endl; return 0; }
11-5
//头文件 #ifndef STONEWT_H_ #define STONEWT_H_ enum Mode{stoneps, intps, floatps}; class Stonewt { private: enum{Lbs_per_stn = 14}; int stone; double pds_left; double pounds; int mode; //这里是从0-2计数，第一个数为0 //重载运算符时用int mode public: void setmode(Mode m); Stonewt(double lbs); Stonewt(int stn, double lbs); Stonewt(); ~Stonewt(); friend Stonewt operator+(const Stonewt & a, const Stonewt & b); friend Stonewt operator-(const Stonewt & a, const Stonewt & b); friend Stonewt operator*(const Stonewt & a, double b); friend Stonewt operator*(double a, const Stonewt & b); friend std::ostream & operator << (std::ostream & os, const Stonewt & s); }; #endif //类实现文件 #include <iostream> #include "U11p5vector.h" using std::cout; void Stonewt::setmode(Mode m) { mode = m; } Stonewt::Stonewt(double lbs) { mode = 2; stone = int (lbs) / Lbs_per_stn; pds_left = int (lbs) % Lbs_per_stn + lbs - int(lbs); pounds = lbs; } Stonewt::Stonewt(int stn, double lbs) { mode = 0; stone = stn; pds_left = lbs; pounds = stn * Lbs_per_stn + lbs; } Stonewt::Stonewt() { mode = 2; stone = pounds = pds_left = 0; } Stonewt::~Stonewt() { } Stonewt operator+(const Stonewt & a, const Stonewt & b) { Stonewt t; if (a.mode == 0) { t.pds_left= a.pds_left + b.pds_left; t.stone = a.stone + b.stone + int (t.pds_left) / Stonewt::Lbs_per_stn; t.pds_left = int (t.pds_left) % Stonewt::Lbs_per_stn + t.pds_left - int(t.pds_left); t.mode = 0; } else if (a.mode == 1) { t.pounds = a.pounds + b.pounds; t.pounds = int (t.pounds + 0.5); t.mode = 1; } else { t.pounds = a.pounds + b.pounds; t.mode = 2; } return t; } Stonewt operator-(const Stonewt & a, const Stonewt & b) { Stonewt t; if (a.mode == 0) { double t1, t2; t1 = a.stone * Stonewt::Lbs_per_stn + a.pds_left; t2 = b.stone * Stonewt::Lbs_per_stn + b.pds_left; t.stone = int ((t1 - t2) / Stonewt::Lbs_per_stn); t.pds_left = (int (t1- t2) % Stonewt::Lbs_per_stn) + t1 - t2 - int(t1 - t2); t.mode = 0; } else if (a.mode == 2) { t.pounds = a.pounds - b.pounds; t.mode = 2; } else { t.pounds = a.pounds - b.pounds; t.pounds = int (t.pounds + 0.5); t.mode = 1; } return t; } Stonewt operator*(const Stonewt & a, double b) { Stonewt t; if (a.mode == 0) { t.pounds = a.pounds * b; t.stone = a.stone * b + int (t.pounds) / Stonewt::Lbs_per_stn; t.pds_left = int (t.pounds) % Stonewt::Lbs_per_stn + t.pounds - int(t.pounds); t.mode = 0; } else if (a.mode == 2) { t.pounds = a.pounds * b; t.mode = 2; } else { t.pounds = a.pounds * b; t.pounds = int (t.pounds + 0.5); t.mode = 1; } return t; } Stonewt operator*(double a, const Stonewt & b) { Stonewt t; if (b.mode == 0) { t.pounds = b.pounds * a; t.stone = b.stone * a + int (t.pounds) / Stonewt::Lbs_per_stn; t.pds_left = int (t.pounds) % Stonewt::Lbs_per_stn + t.pounds - int(t.pounds); t.mode = 0; } else if (b.mode == 2) { t.pounds = b.pounds * a; t.mode = 2; } else { t.pounds = b.pounds * a; t.pounds = int (t.pounds + 0.5); t.mode = 1; } return t; } std::ostream & operator << (std::ostream & os, const Stonewt & s) { if (s.mode == 0) { os << s.stone << " stone, " << s.pds_left << " pounds "; } else if (s.mode == 2) { os << s.pounds << " pounds "; } else if (s.mode == 1) { os << int (s.pounds + 0.5) << " pounds "; } else { os << "Stonewt object mode is invalid"; } } //主程序文件 #include <iostream> using std::cout; #include "U11p5vector.h" void display(const Stonewt & st, int n); int main() { Stonewt incognito; Stonewt wolfe(285.9); Stonewt alex(334.4); cout << "The incognito weighed: "; cout << incognito; cout << "The alex weighed: "; cout << alex; cout << "The wolfe weighed: "; cout << wolfe; cout << "Output in int:"; wolfe.setmode(intps); cout << wolfe; cout << "Output in stone:"; wolfe.setmode(stoneps); cout << wolfe; //这里的输出格式由第一个参数的形式决定 cout << "The ( alex + wolfe ) weighed: "; cout << alex + wolfe; cout << "The ( alex - wolfe ) weighed: "; cout << alex - wolfe; cout << "The wolfe * 2 weighed: "; cout << wolfe * 2.0;//wolfe的形式已经变成英石磅的形式 cout << "The 2 * alex weighed: "; cout << 2.0 * alex; incognito = 325.2; cout << "After dinner, the President weighed: "; cout << incognito; display(incognito, 2); cout << "No stone left unearned "; return 0; } void display(const Stonewt & st, int n) { for (int i = 0; i < n; i++) { cout << "Wow! "; cout << st; } }
11-6
//头文件 #ifndef STONEWT_H_ #define STONEWT_H_ enum Mode{stoneps, intps, floatps}; class Stonewt { private: enum{Lbs_per_stn = 14}; int stone; double pds_left; double pounds; int mode; //这里是从0-2计数，第一个数为0 //重载运算符时用int mode public: void setmode(Mode m); Stonewt(double lbs); Stonewt(int stn, double lbs); Stonewt(); ~Stonewt(); friend Stonewt operator+(const Stonewt & a, const Stonewt & b); friend Stonewt operator-(const Stonewt & a, const Stonewt & b); friend Stonewt operator*(const Stonewt & a, double b); friend Stonewt operator*(double a, const Stonewt & b); friend bool operator>(const Stonewt & a, const Stonewt & b); friend bool operator<(const Stonewt & a, const Stonewt & b); friend bool operator>=(const Stonewt & a, const Stonewt & b); friend bool operator<=(const Stonewt & a, const Stonewt & b); friend bool operator==(const Stonewt & a, const Stonewt & b); friend bool operator!=(const Stonewt & a, const Stonewt & b); friend std::ostream & operator << (std::ostream & os, const Stonewt & s); }; #endif //类实现文件 #include <iostream> #include "U11p6vector.h" using std::cout; void Stonewt::setmode(Mode m) { mode = m; } Stonewt::Stonewt(double lbs) { mode = 2; stone = int (lbs) / Lbs_per_stn; pds_left = int (lbs) % Lbs_per_stn + lbs - int(lbs); pounds = lbs; } Stonewt::Stonewt(int stn, double lbs) { mode = 0; stone = stn; pds_left = lbs; pounds = stn * Lbs_per_stn + lbs; } Stonewt::Stonewt() { mode = 2; stone = pounds = pds_left = 0; } Stonewt::~Stonewt() { } Stonewt operator+(const Stonewt & a, const Stonewt & b) { Stonewt t; if (a.mode == 0) { t.pds_left= a.pds_left + b.pds_left; t.stone = a.stone + b.stone + int (t.pds_left) / Stonewt::Lbs_per_stn; t.pds_left = int (t.pds_left) % Stonewt::Lbs_per_stn + t.pds_left - int(t.pds_left); t.mode = 0; } else if (a.mode == 1) { t.pounds = a.pounds + b.pounds; t.pounds = int (t.pounds + 0.5); t.mode = 1; } else { t.pounds = a.pounds + b.pounds; t.mode = 2; } return t; } Stonewt operator-(const Stonewt & a, const Stonewt & b) { Stonewt t; if (a.mode == 0) { double t1, t2; t1 = a.stone * Stonewt::Lbs_per_stn + a.pds_left; t2 = b.stone * Stonewt::Lbs_per_stn + b.pds_left; t.stone = int ((t1 - t2) / Stonewt::Lbs_per_stn); t.pds_left = (int (t1- t2) % Stonewt::Lbs_per_stn) + t1 - t2 - int(t1 - t2); t.mode = 0; } else if (a.mode == 2) { t.pounds = a.pounds - b.pounds; t.mode = 2; } else { t.pounds = a.pounds - b.pounds; t.pounds = int (t.pounds + 0.5); t.mode = 1; } return t; } Stonewt operator*(const Stonewt & a, double b) { Stonewt t; if (a.mode == 0) { t.pounds = a.pounds * b; t.stone = a.stone * b + int (t.pounds) / Stonewt::Lbs_per_stn; t.pds_left = int (t.pounds) % Stonewt::Lbs_per_stn + t.pounds - int(t.pounds); t.mode = 0; } else if (a.mode == 2) { t.pounds = a.pounds * b; t.mode = 2; } else { t.pounds = a.pounds * b; t.pounds = int (t.pounds + 0.5); t.mode = 1; } return t; } Stonewt operator*(double a, const Stonewt & b) { Stonewt t; if (b.mode == 0) { t.pounds = b.pounds * a; t.stone = b.stone * a + int (t.pounds) / Stonewt::Lbs_per_stn; t.pds_left = int (t.pounds) % Stonewt::Lbs_per_stn + t.pounds - int(t.pounds); t.mode = 0; } else if (b.mode == 2) { t.pounds = b.pounds * a; t.mode = 2; } else { t.pounds = b.pounds * a; t.pounds = int (t.pounds + 0.5); t.mode = 1; } return t; } bool operator>(const Stonewt & a, const Stonewt & b) { double t1, t2; if (a.mode == 0) { t1 = a.stone * Stonewt::Lbs_per_stn + a.pds_left; } else { t1 = a.pounds; } if (b.mode == 0) { t2 = b.stone * Stonewt::Lbs_per_stn + b.pds_left; } else { t2 = b.pounds; } return t1 > t2; } bool operator<(const Stonewt & a, const Stonewt & b) { double t1, t2; if (a.mode == 0) { t1 = a.stone * Stonewt::Lbs_per_stn + a.pds_left; } else { t1 = a.pounds; } if (b.mode == 0) { t2 = b.stone * Stonewt::Lbs_per_stn + b.pds_left; } else { t2 = b.pounds; } return t1 < t2; } bool operator>=(const Stonewt & a, const Stonewt & b) { double t1, t2; if (a.mode == 0) { t1 = a.stone * Stonewt::Lbs_per_stn + a.pds_left; } else { t1 = a.pounds; } if (b.mode == 0) { t2 = b.stone * Stonewt::Lbs_per_stn + b.pds_left; } else { t2 = b.pounds; } return t1 >= t2; } bool operator<=(const Stonewt & a, const Stonewt & b){ double t1, t2; if (a.mode == 0) { t1 = a.stone * Stonewt::Lbs_per_stn + a.pds_left; } else { t1 = a.pounds; } if (b.mode == 0) { t2 = b.stone * Stonewt::Lbs_per_stn + b.pds_left; } else { t2 = b.pounds; } return t1 <= t2; } bool operator==(const Stonewt & a, const Stonewt & b){ double t1, t2; if (a.mode == 0) { t1 = a.stone * Stonewt::Lbs_per_stn + a.pds_left; } else { t1 = a.pounds; } if (b.mode == 0) { t2 = b.stone * Stonewt::Lbs_per_stn + b.pds_left; } else { t2 = b.pounds; } return t1 == t2; } bool operator!=(const Stonewt & a, const Stonewt & b) { { double t1, t2; if (a.mode == 0) { t1 = a.stone * Stonewt::Lbs_per_stn + a.pds_left; } else { t1 = a.pounds; } if (b.mode == 0) { t2 = b.stone * Stonewt::Lbs_per_stn + b.pds_left; } else { t2 = b.pounds; } return t1 != t2; } } std::ostream & operator << (std::ostream & os, const Stonewt & s) { if (s.mode == 0) { os << s.stone << " stone, " << s.pds_left << " pounds "; } else if (s.mode == 2) { os << s.pounds << " pounds "; } else if (s.mode == 1) { os << int (s.pounds + 0.5) << " pounds "; } else { os << "Stonewt object mode is invalid"; } } //主程序文件 #include <iostream> #include "U11p6vector.h" using std::cout; using std::cin; int main() { Stonewt incognito[6]; incognito[0] = 285.9; incognito[1] = 235.6; incognito[2] = 262.4; for (int i= 3; i < 6; i++) { double n; cout << "Please enter the number #" << i+1 << ": "; cin >> n; incognito[i] = n; } Stonewt stand(11, 0); Stonewt max; Stonewt min; int imax; int imin; max = min = incognito[0]; imax = imin = 0; for (int i= 0; i < 6; i++) { if (min > incognito[i]) { min = incognito[i]; imin = i; } if (max < incognito[i]) { max = incognito[i]; imax = i; } } cout << "The max is: " << "incognito[" << imax <<"]: " << max; cout << "The min is: " << "incognito[" << imin <<"]: " << min; cout << "The weight more than 11 stone is: "; for (int i= 0; i < 6; i++) { if (incognito[i] > stand) cout << "incognito[" << i <<"]: " << incognito[i]; } return 0; }
11-7
//头文件 #ifndef COMPLEX0_H_ #define COMPLEX0_H_ #include <iostream> class complex { private: double x; double y; public: complex(); complex(double n1, double n2); void reset(double n1, double n2); ~complex(); //友元函数重载 friend complex operator+(const complex & a, const complex & b); friend complex operator-(const complex & a, const complex & b); friend complex operator*(const complex & a, const complex & b); friend complex operator*(double a, const complex & b); friend complex operator~(const complex & a); friend std::ostream & operator << (std::ostream & os, const complex & c); friend std::istream & operator >> (std::istream & ins, complex & c);//输入时，会产生改变，不用const }; #endif //类实现文件 #include <iostream> #include "U11p7complex0.h" using std::cout; complex::complex() { x = y = 0; } complex::complex(double n1, double n2) { x = n1; y = n2; } void complex::reset(double n1, double n2) { x = n1; y = n2; } complex::~complex() { } //友元函数重载 complex operator+(const complex & a, const complex & b) { complex t; t.x = a.x + b.x; t.y = a.y + b.y; return t; } complex operator-(const complex & a, const complex & b) { complex t; t.x = a.x - b.x; t.y = a.y - b.y; return t; } complex operator*(const complex & a, const complex & b) { complex t; t.x = a.x * b.x - a.y * b.y; t.y = a.x * b.y + a.y * b.x; return t; } complex operator*(double a, const complex & b) { complex t; t.x = a * b.x; t.y = a * b.y; return t; } complex operator~(const complex & a) { complex t; t.x = a.x; t.y = -a.y; return t; } std::istream & operator >> (std::istream & ins, complex & c) { std::cout << "real: "; if(!(ins >> c.x)) return ins; std::cout << "imaginary: "; ins >> c.y; return ins; } std::ostream & operator << (std::ostream & os, const complex & c) { os << "(" << c.x << ", " << c.y << "i)"; return os; } //主文件 #include <iostream> using namespace std; #include "U11p7complex0.h" int main() { complex a(3.0, 4.0); complex c; cout << "Enter a complex number (q to quit): "; while (cin >> c) { cout << "c is " << c << ' '; cout << "complex conjugate is " << ~c << ' '; cout << "a is " << a << ' '; cout << "a + c is " << a + c << ' '; cout << "a - c is " << a - c << ' '; cout << "a * c is " << a * c << ' '; cout << "2 * c is " << 2 * c << ' '; cout << "Enter a complex number (q to quit): "; } cout << "Done! "; return 0; }