function-call.cpp

来自「压缩包里有教材<<C++模式设计-基于QT4开源跨平台开发框架&gt」· C++ 代码 · 共 48 行

#include <iostream>
using namespace std;
//start id=classdef
class SignatureDemo {
public:
    SignatureDemo(int val) : m_Val(val) {}
    void demo(int n)
        {cout << ++m_Val << "\tdemo(int)" << endl;}
    void demo(int n) const /* overloaded on const-ness */  
        {cout << m_Val << "\tdemo(int) const" << endl;}
/*  void demo(const int& n)   
      {cout << ++m_Val << "\tdemo(int&)" << endl;}  */ /* clashes
      with previous function */
    void demo(short s)  
        {cout << ++m_Val << "\tdemo(short)" << endl;}
    void demo(float f)  
        {cout << ++m_Val << "\tdemo(float)" << endl;}
    void demo(float f) const 
        {cout << m_Val << "\tdemo(float) const" << endl;}
    void demo(double d)
        {cout << ++m_Val << "\tdemo(double)" << endl;}
private:
    int m_Val;
};
//end
//start id=clientcode
int main() {
    SignatureDemo sd(5);
    const SignatureDemo csd(17);
    sd.demo(2);    
    csd.demo(2);   /* const version is called. */
    int i = 3;
    sd.demo(i);
    short s = 5;
    sd.demo(s);
    csd.demo(s); /* Non-const short can not be called,
                so a promotion to int is required to call
                the const int version. */
    sd.demo(2.3);   /* This is double, not float. */
    float f(4.5);   
    sd.demo(f);
    csd.demo(f);    
    csd.demo(4.5);  
    return 0;
}
//end