Default Arguments

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9.5 Default Arguments

Default values take effect when arguments are omitted in the declaration of objects.
If a parameter is provided a default value, also all the following parameters should be supplied default values.

#include <iostream>
using namespace std;

template <typename T = int, int i = 100>
class Init
{
   public:
      Init()
      {
         T x = (T) i;
         cout << i << ” ” << x << endl;
      }
};

int main()
{
   Init<char, 100> a;
   Init<> b;
}

#include <iostream>
using namespace std;

template <typename T = int, int i = 100>
class Init
{
   public:
      Init();
};

int main()
{
   Init<char, 100> a;
   Init<> b;
}

template <typename T, int i>
Init<T,i>::Init()
{
   T x = (T) i;
   cout << i << ” ” << x << endl;
}

100 d
100 100

[dfltyp.cpp][odfltyp.cpp]