其他未完成

day10/stl_algorithm_demo/d1.cpp

@@ -0,0 +1,33 @@
+// 函数对象
+// 仿函数: 一元，二元仿函数
+#include <iostream>
+
+using namespace std;
+
+// 一元仿函数
+class A
+{
+public:
+    A(int n) : n(n) {}
+    int n;
+    // 重载 operator() 运算符，只要调用 A 对象的 (int x) ，就会给对象的对应成员对象加一个 x
+    A &operator()(int i)
+    {
+        this->n += i;
+        return *this;
+    }
+};
+
+void print(A a, int n) // A a = A(30)
+{
+    a(n);
+    cout << "a.n = " << a.n << endl;
+}
+
+int main()
+{
+    // 打印 a 对象的值加额外的值的结果
+    print(A(20), 3); // A(20) 会创建一个匿名对象
+
+    return 0;
+}

day10/stl_algorithm_demo/d2.cpp

@@ -0,0 +1,59 @@
+// 谓词
+// gt 大于， ge 大于等于
+// lt 小于， le 小于等于
+// eq 等于， ne 小于等于
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+using namespace std;
+
+class GTFive // 一元谓词
+{
+public:
+    bool operator()(int n)
+    {
+        return n > 5;
+    }
+};
+
+class GT // 二元谓词
+{
+public:
+    bool operator()(const int &n1, const int &n2)
+    {
+        return n1 > n2;
+    }
+};
+
+void printGTF(GTFive gtf, int *p, int size)
+{
+    for (int i = 0; i < size; i++)
+    {
+        if (gtf(p[i]))
+            cout << p[i] << " ";
+    }
+    cout << endl;
+}
+
+void print(int *p, int size, GT gt, int n)
+{
+    for (int i = 0; i < size; i++)
+    {
+        if (gt(p[i], n))
+            cout << p[i] << " ";
+    }
+    cout << endl;
+}
+
+int main()
+{
+    int ms[] = {1, 2, 4, 7, 9, 20};
+    cout << "大于 5 的元素" << endl;
+    printGTF(GTFive(), ms, 6);
+
+    cout << "大于 7 的元素" << endl;
+    print(ms, 6, GT(), 7);
+
+    return 0;
+}

day10/stl_algorithm_demo/d3.cpp

@@ -0,0 +1,39 @@
+// 算术类函数对象
+// 算术类函数对象
+#include <iostream>
+#include <set>
+#include <algorithm>
+
+using namespace std;
+
+// template <typename T>
+void print(typename set<int>::const_iterator start,
+           typename set<int>::const_iterator end, plus<int> pl, int m)
+{
+    for (; start != end; start++)
+    {
+        cout << pl(*start, m) << " ";
+    }
+    cout << endl;
+}
+
+void print(typename set<int>::const_iterator start,
+           typename set<int>::const_iterator end, multiplies<int> mul, int m)
+{
+    for (; start != end; start++)
+    {
+        cout << mul(*start, m) << " ";
+    }
+    cout << endl;
+}
+
+int main()
+{
+    int m[] = {1, 2, 3, 4, 8, 5, 1, 2};
+    // set 会自动过滤重复，并排序
+    set<int> s(m, m + sizeof(m) / sizeof(m[0]));
+    print(s.begin(), s.end(), plus<int>(), 1);
+    print(s.begin(), s.end(), multiplies<int>(), 3);
+
+    return 0;
+}

day10/stl_algorithm_demo/f1.cpp

@@ -0,0 +1,59 @@
+#include <iostream>
+#include <set>
+#include <algorithm>
+
+using namespace std;
+
+// template <typename T>
+void print(typename set<int>::const_iterator start,
+           typename set<int>::const_iterator end, plus<int> pl, int m)
+{
+    for (; start != end; start++)
+    {
+        cout << pl(*start, m) << " ";
+    }
+    cout << endl;
+}
+
+void print(typename set<int>::const_iterator start,
+           typename set<int>::const_iterator end, multiplies<int> mul, int m)
+{
+    for (; start != end; start++)
+    {
+        cout << mul(*start, m) << " ";
+    }
+    cout << endl;
+}
+
+void show(int n)
+{
+    cout << n << " ";
+}
+
+// 二元仿函数
+class PrintPlus : public binary_function<int, int, void>
+{
+public:
+    void operator()(const int &n1, const int &n2) const
+    {
+        cout << n1 << "+" << n2 << " = " << n1 + n2 << endl;
+    }
+};
+
+int main()
+{
+    int m[] = {1, 2, 3, 4, 8, 5, 1, 2};
+    // set 会自动过滤重复，并排序
+    set<int> s(m, m + sizeof(m) / sizeof(m[0]));
+    // print(s.begin(), s.end(), plus<int>(), 1);
+    // print(s.begin(), s.end(), multiplies<int>(), 3);
+
+    // for_each(s.begin(), s.end(), show);
+    // cout << endl;
+
+    // PrintPlus 测试
+    // for (int i = 0; i < 6; i++)
+    for_each(s.begin(), s.end(), bind1st(PrintPlus(), i));
+
+    return 0;
+}

day10/stl_algorithm_demo/f2.cpp

@@ -0,0 +1,25 @@
+#include <iostream>
+#include <set>
+#include <algorithm>
+
+using namespace std;
+
+class PrintGt5Adapter : public binary_function<int, int, void>
+{
+public:
+    void operator()(const int &n1, const int &n2) const
+    {
+        if (n1 > n2)
+            cout << n1 << " ";
+    }
+};
+
+int main()
+{
+    int m[] = {1, 2, 3, 4, 8, 5, 1, 2};
+    set<int> s(m, m + sizeof(m) / sizeof(m[0]));
+
+    for_each(s.begin(), s.end(), bind2nd(PrintGt5Adapter(), 2));
+
+    return 0;
+}

day10/stl_algorithm_demo/f3.cpp

@@ -0,0 +1,43 @@
+// 取反适配器
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+// 自定义一个适配器，只需要容器中元素即可。
+class GT5 : public unary_function<int, bool>
+{
+public:
+    bool operator()(const int &n) const
+    {
+        return n > 5;
+    }
+};
+
+class GTN : public binary_function<int, int, bool>
+{
+public:
+    bool operator()(const int &n1, const int &n2) const
+    {
+        return n1 > n2;
+    }
+};
+
+int main()
+{
+    int m[] = {1, 2, 2, 3, 5, 10};
+    vector<int> v;
+    v.assign(m, m + sizeof(m) / sizeof(m[0]));
+
+    // find_if(start, end, _callback) 返回查找到的第一个迭代器的位置
+    vector<int>::iterator ret = find_if(v.begin(), v.end(), not1(bind2nd(greater<int>(), 3)));
+    cout << *ret << endl;
+
+    ret = find_if(v.begin(), v.end(), GT5());
+    cout << *ret << endl;
+
+    ret = find_if(v.begin(), v.end(), bind2nd(GTN(), 3));
+    cout << *ret << endl;
+
+    return 0;
+}

day10/stl_algorithm_demo/f4.cpp

@@ -0,0 +1,26 @@
+// 函数指针适配
+// 使用 ptr_fun<>() 适配函数指针
+// <> 中的第一个参数是函数指针的类型，第二个参数是函数指针的参数类型，第三个参数是函数指针的返回值类型
+// bind1st() 和 bind2nd() 适配函数对象
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+bool gtn(int n1, int n2)
+{
+    return n1 > n2;
+}
+
+int main()
+{
+    int m[] = {1, 2, 2, 3, 5, 10};
+    vector<int> v;
+    v.assign(m, m + sizeof(m) / sizeof(m[0]));
+
+    vector<int>::iterator ret = find_if(v.begin(), v.end(), bind2nd(ptr_fun<int, int, bool>(gtn), 3));
+    cout << *ret << endl;
+
+    return 0;
+}

day10/stl_algorithm_demo/f5.cpp

@@ -0,0 +1,39 @@
+// mem_fn 有两个重载版本：
+// 用法1：mem_fn(&MyClass::printMessage) 用于将成员函数转换为函数对象
+// 用法2：mem_fn(&MyClass::printMessage)(&obj, "hello world") 用于调用成员函数
+// mem_fn 是一个函数模板，它接受一个成员函数指针或成员函数引用，并返回一个函数对象，该对象可以调用相应的成员函数。
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+class Stu
+{
+private:
+    string name;
+    int age;
+
+public:
+    Stu(const string &name, int age) : name(name), age(age) {}
+
+public:
+    void show()
+    {
+        cout << "name is " << name << ", age is " << age << endl;
+    }
+};
+
+int main()
+{
+    vector<Stu> vs;
+    vs.push_back(Stu("disen", 18));
+    vs.push_back(Stu("lucy", 20));
+    vs.push_back(Stu("jack", 15));
+    vs.push_back(Stu("mack", 19));
+
+    // 遍历容器中所有成员，成员函数作为仿函数时，则通过容器成员调用它的仿函数
+    for_each(vs.begin(), vs.end(), mem_fun_ref(&Stu::show));
+
+    return 0;
+}

day10/stl_algorithm_demo/f6.cpp

@@ -0,0 +1,30 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+#include <functional>
+
+using namespace std;
+using namespace std::placeholders;
+
+int main()
+{
+    int m[] = {1, 2, 2, 3, 5, 10};
+    vector<int> v;
+    v.assign(m, m + sizeof(m) / sizeof(m[0]));
+
+    int target = 3;
+
+    // 使用 std::bind 适配 std::equal_to
+    vector<int>::iterator ret = adjacent_find(v.begin(), v.end(), bind(equal_to<int>(), _1, 3));
+    cout << *(++ret) << endl;
+
+    if (ret != v.end())
+    {
+        cout << "Found adjacent elements equal to " << target << "." << endl;
+    }
+    else
+    {
+        cout << "No adjacent elements equal to " << target << " found." << endl;
+    }
+    return 0;
+}