指向函数的指针

来源：互联网发布：零基础编程入门编辑：程序博客网时间：2024/06/10 20:43
#include <iostream>#include <string>#include <vector>using namespace std;typedef bool (*cmpFcn) (const string&, const string&);// typedef简化指针的定义，bool lengthCompare(const string &s1, const string &s2){return s1.size() == s2.size();}void ff(vector<double> vec){cout << "ff(vector<double> vec)" << endl;}void ff(unsigned int x){cout << "ff(unsigned int x)" << endl;}int demo (int *p, int a){return 12;}int (*ff(int x))(int *, int)  //ff是一个函数，有一个形参x，返回结果是一个函数指针，int(*)(int *, int){cout << x << endl;return demo;}void useBigger(const string &s1, const string &s2, bool (*pf)(const string&, const string&)){cout << pf(s1,s2) << endl;}int main (){bool (*pf)(const string &, const string &); // pf是一个指针，指向函数的指针：函数类型，void (*pf7)(vector<double>) = &ff;cmpFcn pf4 = lengthCompare;useBigger("hi", "function", pf4);  // 函数的名称就是一个指针，int a = 5;int *pa;cout << ff(2)(&a, a) << endl;  // 一个输出是2，另一个输出是12，//pf 是一个局部变量，// bool (*pf2)(const string&, const string&); //bool (*pf3)(const string&, const string&); cmpFcn pf2;cmpFcn pf3 = 0;pf2 = lengthCompare;pf3 = lengthCompare;pf = &lengthCompare;cout << lengthCompare("hello", "pointer") << endl;  // 输出是0，cout << (*pf)("hello", "point") << endl;  // 输出是1，return 0;}
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