Question

我想知道用Line().setLength(6.0);创建对象之间的区别是什么？和 Line line; line.setLength(6.0); 编译后结果是否相同？

#include <iostream>

using namespace std;

class Line {
   public:
      void setLength( double len );
      double getLength( void );
      Line();   // This is the constructor declaration
      ~Line();  // This is the destructor: declaration

   private:
      double length;
};

// Member functions definitions including constructor
Line::Line(void) {
   cout << "Object is being created" << endl;
}

Line::~Line(void) {
   cout << "Object is being deleted" << endl;
}

void Line::setLength( double len ) {
   length = len;
}

double Line::getLength( void ) {
   return length;
}

// Main function for the program
int main( ) {
   Line().setLength(6.0);

   Line line;
   line.setLength(6.0); 
   return 0;
}

Answer 1

结果应始终相同。但是Line().setLength(6.0);表示您将来无法更改该行的属性，而使用Line line; line.setLength(6.0);可以访问变量line，从而更改该行的属性。

创建变量实例的不同之处是什么？

1 个答案: