C + + implicit conversions

#include <iostream>using namespace Std;class a{int a;public:a (int n): A (n) {cout << "constructor!" << Endl;} ~a () {cout << "destructor!" << Endl;}}; int main () {A A = 10;return 0;}

Program output:

constructor!

destructor!

A = 10; Such a grammar is passed, why? Because of the implicit conversion of the constructor, the implicit conversion rule agrees to initialize the object with a single parameter, which invokes a constructor with a parameter in the class, which can have a default value of just one parameter.

In addition, add explicitkeyword. To eliminate this implicit conversion , add Explicitkeyword to the preceding constructor and you will find that the compilation failed.

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C + + implicit conversions