default-arguments

In the following code: struct Foo { Foo(int x=0); }; Does the constructor count as a default constructor? C++98 §12.1/5 (emphasis mine) : A default constructor for a class X is a constructor of X that can be called without an argument. If there is no user-declared constructor for class X, a default constructor is implicitly declared. So yes, it does count as a default constructor. See also . 来源： https://stackoverflow.com/questions/11250690/in-c-is-a-constructor-with-only-default-arguments-a-default-constructor

Asked because of this : Default argument in c++ Say I have a function such as this: void f(int p1=1, int p2=2, int p3=3, int p4=4); And I want to call it using only some of the arguments - the rest will be the defaults. Something like this would work: template<bool P1=true, bool P2=true, bool P3=true, bool P4=true> void f(int p1=1, int p2=2, int p3=3, int p4=4); // specialize: template<> void f<false, true, false, false>(int p1) { f(1, p1); } template<> void f<false, true, true, false>(int p1, int p2) { f(1, p1, p2); } // ... and so on. // Would need a specialization for each combination of

In PHP you can call a function. by not calling all parameters by using these statement. function test($t1 ='test1',$t2 ='test2',$t3 ='test3') { echo "$t1, $t2, $t3"; } And you can just use the function like this test(); So lets just say I want the last one to be different but not the others. The only way I can thing of is by doing this with no success: test('test1','test2','hi i am different'); I tried this: test(,,'hi i am different'); test(default,default,'hi i am different'); What is the best way to do something like this? Use arrays : function test($options = array()) { $defaults = array(