c++ - 如何在 C++ 中修复 "no matching function to call to..."？

Question

嘿，我想将我的 wav 文件的二进制数据加载到我的数组中，但我收到类似这样的错误:“不匹配调用 'std::basic_ifstream(Array&, size_t&)' 的函数”，我想这样做使用模板，有人知道如何解决这个问题吗？

int main(){


    ifstream infile("soundeffect.wav", std::ios::binary);

    infile.seekg(0, infile.end);
    size_t length = infile.tellg();
    infile.seekg(44, infile.beg);

    Array<int> array(length);


    infile.read(array, length); //error in this line

     return 0;
}

Answer 1

I get an error like: "not matching function for call to 'std::basic_ifstream(Array&, size_t&)'"

Array is a class I wrote and yes I put 'using namepace std;'

如果我很了解你有类似的东西:

#include <fstream>

using namespace std;

template<typename K>
class Array {
  public:
    Array(size_t ln) { /*...*/ }
  // ...
};

int main(){
  ifstream infile("soundeffect.wav", std::ios::binary);

  infile.seekg(0, infile.end);
  size_t length = infile.tellg();
  infile.seekg(44, infile.beg);

  Array<int> array(length);

  infile.read(array, length); //error in this line

  return 0;
}

当我编译时我也有

c.cc: In function ‘int main()’: c.cc:21:28: error: no matching function for call to ‘std::basic_ifstream::read(Array&, size_t&)’ infile.read(array, length); //error in this line

这是正常的，因为没有理由 ifstream::read 知道如何读取数组

一种方法是在 Array 上定义操作 read ，例如

#include <fstream>

using namespace std;

template<typename K>
class Array {
  public:
    Array(size_t ln) : len(ln) { /* ... */ }
    istream & read(istream & in, size_t & len);
    // ...
  private:
    size_t len;
  // ...
};      

// ln is an input-output var allowing to know how much elements
// was read, returns the istream to know if an error occurs
// and which one
template<typename K>
istream & Array<K>::read(istream & in, size_t & ln) {
  size_t n = min(ln, len);

  for (ln = 0; ln != n; ++ln)
    if (! in.read(??, ??))
      break;

  return in;
}

int main(){
  ifstream infile("soundeffect.wav", std::ios::binary);

  infile.seekg(0, infile.end);
  size_t length = infile.tellg();
  infile.seekg(44, infile.beg);

  Array<int> array(length);

  array.read(infile, length);

  return 0;
}

但是你确定你可以定义一个通用类 Array 允许将 wav 文件读入 Array<int> ？