代碼如下:

#include <iostream> #include <string> using namespace std;//函數對象在使用時，可以像普通函數那樣調用，可以有參數，可以有返回值 class MyAdd { public:int operator()(int a, int b){return a + b;} };void test01() {MyAdd myAdd;cout << myAdd(10, 10) << endl; }//函數對象可以有自己的狀態 class MyPrint { public:MyPrint(){count = 0;}void operator()(string test){cout << test << endl;count++;}int count = 0; };void test02() {MyPrint myPrint;myPrint("hello world");myPrint("hello world");myPrint("hello world");cout << "count = " << myPrint.count << endl;}//函數對象可以作為參數傳遞 void doPrint(MyPrint &mp, string test) {mp(test); }void test03() {MyPrint myPrint;doPrint(myPrint, "hello c++"); }int main() {test01();test02();test03();return 0; }

測試結果:

總結:

一元謂詞
代碼如下:

#include <iostream> #include <vector> #include <algorithm> using namespace std;struct GreaterFive {bool operator()(int a){return a > 5;} };void test01() {vector<int>v;for (int i = 0; i < 10; i++){v.push_back(i);}vector<int>::iterator it = find_if(v.begin(), v.end(), GreaterFive());if (it == v.end()){cout << "no find" << endl;}else{cout << "find" << *it << endl;}}int main() {test01();return 0; }

測試結果:

總結:

二元謂詞
代碼如下:

#include <iostream> #include <vector> #include <algorithm> using namespace std;class cmp { public:bool operator()(int a, int b){return a > b;} };void test01() {vector<int>v;v.push_back(10);v.push_back(40);v.push_back(20);v.push_back(30);v.push_back(50);sort(v.begin(), v.end());for (vector<int>::iterator it = v.begin(); it != v.end(); it++){cout << *it << " ";}cout << endl;cout << "---------------------------------------" << endl;sort(v.begin(), v.end(), cmp());for (vector<int>::iterator it = v.begin(); it != v.end(); it++){cout << *it << " ";}cout << endl;}int main() {test01();return 0; }

測試結果:

總結:

代碼如下:

#include <iostream> #include <functional> using namespace std;void test01() {negate<int> n;cout << n(50) << endl; }void test02() {plus<int>p;cout << p(10, 20) << endl; }int main() {test01();test02();return 0; }

測試結果:

總結:

代碼如下:

#include <iostream> #include <vector> #include <algorithm> using namespace std;class cmp { public:bool operator()(int a, int b){return a > b;} };void test01() {vector<int>v;v.push_back(10);v.push_back(20);v.push_back(50);v.push_back(40);v.push_back(90);v.push_back(70);for (vector<int>::iterator it = v.begin(); it != v.end(); it++){cout << *it << " ";}cout << endl;sort(v.begin(), v.end(), greater<int>());for (vector<int>::iterator it = v.begin(); it != v.end(); it++){cout << *it << " ";}cout << endl;}int main() {test01();return 0; }

測試結果:

總結:

代碼如下:

#include <iostream> #include <functional> #include <vector> #include <algorithm> using namespace std;void test01() {vector<bool> v;v.push_back(true);v.push_back(false);v.push_back(true);v.push_back(false);for (vector<bool>::iterator it = v.begin(); it != v.end(); it++){cout << *it << " ";}cout << endl;vector<bool> v2;v2.resize(v.size());transform(v.begin(), v.end(), v2.begin(), logical_not<bool>());for (vector<bool>::iterator it = v2.begin(); it != v2.end(); it++){cout << *it << " ";}cout << endl;}int main() {test01();return 0; }

測試結果:

總結:

總結

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