Default parameters for C + + functions

Default parameters of a common function

# include<iostream>using namespace std;void func (int m=0,int n=1)//m=0, called the function's default parameter, is also called the default parameter. The default parameter can have one or more. {cout<< "M:" <<m<< "\ T" << "N:" <<n<<endl;} int main () {func (); func (3,5);//When the function is called, the default argument is called when there are no arguments, and if there are arguments, the parameters prevail. return 0;}

Operation Result:

Second, the default parameters of the member function

# include<iostream>using namespace Std;class a{public:void set (int =20,int =3);//It is permissible to write. void Count (bool=false);p rivate:int w;int h;}; int main () {A a;cout<< "when using the default function:" <<endl;a.set (); A.count (); A.count (true);cout<<endl<< " When re-copying: "<<endl;a.set (5,2);    A.count (); A.count (true);//So the default function also implements the overloaded function. return 0;} void A::set (int width,int height) {w=width;h=height;} void A::count (bool val) {if (val==true) {cout<< "Val value is true:" <<W*H<<ENDL;} elsecout<< "Val value is false:" <<W*H/2<<ENDL;}

Operation Result:

Comments:

1, the overloaded function is easy to use and easy to understand. The function of the default parameter is easily ignored if it is not labeled, and is easily overwritten by a function with the same name as the parameter.

2. A function overloaded with a default parameter is the numeric value of the parameter, and the overloaded function overloads the type of the parameter.

Default parameters for C + + functions