C++primer5th课后题13章13.13、13.22、13.26、13.27

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习题13.13

class Employee {    static int sn;    string name;    int mysn;public:    Employee() { mysn = sn++; }    Employee(const string &n) :name(n) { mysn = sn++; }    Employee(const Employee&rhs) { name = rhs.name; mysn = rhs.mysn; }//mysn = sn++; }    Employee& operator = (const Employee& rhs) { name = rhs.name; return *this; }    const string& get_name() { return name; }    const int& get_mysn() { return mysn; }};int Employee::sn = 0;class numbered {private:    static int seq ;public:    numbered() { mysn = seq++; };    numbered(const numbered&) { mysn = seq++; }    int mysn;};void f(Employee &s){    cout << s.get_name() << ":" << s.get_mysn() << endl;}int main(){    Employee a("高"), b = a, c;// b = a,拷贝初始化，拷贝构造函数    c = b;//赋值操作符    f(a);    f(b);    f(c);}

习题13.22

class HasPtr {public:    HasPtr(const string &s = string()) : ps(new string(s)), i(0) {}    //HasPtr(const HasPtr &hp) : ps(new string(*hp.ps)), i(hp.i){}    HasPtr(const HasPtr &hp) { ps = new string(*hp.ps); i = hp.i; }    HasPtr& operator = (const HasPtr &rhs) { auto newps = new string(*rhs.ps); delete ps; ps = newps; i = rhs.i; return *this; }    HasPtr& operator = (const string &s) { *ps = s; return *this; }    string& operator*() { return *ps; }    ~HasPtr() { delete ps; }private:    string *ps;    int i;};int main(){    HasPtr h("hi man!");    HasPtr h2(h);    HasPtr h3 = h;z    h2 = "hi doode!";    h3 = "hi boy!";    cout << "h: " << *h << endl;    cout << "h2: " << *h2 << endl;    cout << "h3: " << *h3 << endl;    return 0;}

习题13.26

#include"myStrBlob.h"int main(){    StrBlob b1;    {        StrBlob b2 = { "a","an","the" };        b1 = b2;        b2.push_back("about");        cout << "b2大小为" << b2.size() << endl;        cout << "b2首尾元素为" << b2.front() << " " << b2.back() << endl;        }    cout << "b1大小为" << b1.size() << endl;    cout << "b1首尾元素为" << b1.front() << " " << b1.back() << endl;    StrBlob b3 = b1;    b3.push_back("next");    cout << "b3大小为" << b3.size() << endl;    cout << "b3首尾元素为" << b3.front() << " " << b3.back() << endl;    cout << "b1全部元素： " << endl;    for (auto i = b1.begin(); neq(i, b1.end()); i.incr())        cout << i.deref() << endl ;}

习题13.27

class HasPtr {    friend void swap(HasPtr &lhs, HasPtr &rhs);public:    HasPtr(const string &s = string()) :ps(new string(s)), i(0), use(new size_t(1)) {}    HasPtr(const HasPtr &p) : ps(p.ps), i(p.i), use(p.use) { ++*use; }    HasPtr& operator = (const HasPtr &p);    HasPtr& operator = (const string &s);    string& operator *();//解引用    bool HasPtr::operator<(const HasPtr&rhs) const;    ~HasPtr();private:    string *ps;    int i;    size_t *use;//引用计数};HasPtr::~HasPtr(){    if (--*use == 0) {        delete use;        delete ps;    }}HasPtr& HasPtr::operator=(const HasPtr &p){    if (--*use == 0) {        delete ps;        delete use;    }    ++*p.use;    use = p.use;    i = p.i;    ps = p.ps;    return *this;}HasPtr& HasPtr::operator=(const string &s){    *ps = s;    return *this;}string& HasPtr::operator*(){    return *ps;}inline void swap(HasPtr&lhs, HasPtr &rhs){    cout << "交换" << *rhs.ps << "和" << *lhs.ps << endl;    swap(lhs.ps, rhs.ps);    swap(lhs.i, rhs.i);}bool HasPtr::operator<(const HasPtr&rhs) const{    return *ps < *rhs.ps;}int main(){    vector<HasPtr> vh;    int n = 100;    for (int i = 0; i < n; i++)        vh.push_back(to_string(n - i));    for (auto p : vh)        cout << *p << " ";    cout << endl;    sort(vh.begin(), vh.end());    for (auto p : vh)        cout << *p << " ";    cout << endl;    return 0;}

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