模板类容器存在自动转换问题

发布于 2024-10-13 04:12:14 字数 785 浏览 1 评论 0原文

我有以下代码：

#include <vector>

template<int Wt = 0>
class fixed {
public:
 explicit fixed(double val = 0) {
  operator=(val);
 }

 ~fixed(){}

 operator double() const {
  return v_;
 }

 double operator =(const double &d){
  if (d>Wt)
   v_ = Wt;
  else
   v_ = d;
  return v_;
 }

private:
 double v_;
};

int main(){
 fixed<5> x;
   std::vector<fixed<6> > v(5);
 //std::vector<fixed<6> > v(5,0);
 //fixed<6> y;
 //v[0] = 0;
 x = x*v[0];
}

在 VS 2005express 和 2010express 中编译出现以下错误：

错误 C2676：二进制“*”：“已修复” 没有定义这个运算符或转换为可接受的类型预定义运算符

如果我取消注释 main 中三行中的任何一行（注释额外的向量），它将编译。如果我使用 gcc 它将编译。有人能暗示这是为什么吗？

该代码是一个较大项目的简化版本，因此不幸的是，这三个解决方案不适合我。

原文

I have the following code:

#include <vector>

template<int Wt = 0>
class fixed {
public:
 explicit fixed(double val = 0) {
  operator=(val);
 }

 ~fixed(){}

 operator double() const {
  return v_;
 }

 double operator =(const double &d){
  if (d>Wt)
   v_ = Wt;
  else
   v_ = d;
  return v_;
 }

private:
 double v_;
};

int main(){
 fixed<5> x;
   std::vector<fixed<6> > v(5);
 //std::vector<fixed<6> > v(5,0);
 //fixed<6> y;
 //v[0] = 0;
 x = x*v[0];
}

Compiling in VS 2005 express and 2010 express gives the following error:

error C2676: binary '*' : 'fixed'
does not define this operator or a
conversion to a type acceptable to the
predefined operator

If I uncomment any of the three lines in the main (commenting the extra vector), it will compile. If I use gcc it will compile. Can anybody give a hint to why this is?

The code is a simplified version of a larger project so the three solutions are unfortunately not options for me.

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荒人说梦 2024-10-20 04:12:14

这似乎是 vc++ 中的一个小故障。如果我添加一个字符串

 x = x* (*&v[0]);

BEFORE the string

x = x*v[0];

(which produced the error) then the error disappears (I use vc 2010 express). GCC compiles this code w/o errors, but only after renaming class fixed to something else (otherwise it complains about ambiguity of this name, i don't know exactly why, maybe it also appears in some gcc headers)

It seems as a glitch in vc++. If I ADD a string