// N4606 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf
#define msg "(175)14.5.1.1 Member functions of class templates [temp.mem.func]p359.cpp"
// Edited by Dr. Ogawa Kiyoshi. Compile procedure and results record.

#include <iostream>
#include <cerrno>

void error(const char* s) {
  std::cout<< s<<std::endl;
}

template<class T> class Array {
  T* v;
  int sz;
public:
  explicit Array(int);
  T& operator[](int);
  T& elem(int i) {
    return v[i];
  }
};

template<class T> T& Array<T>::operator[](int i) {
  if (i<0 || sz<=i) error("Array: range error");
  return v[i];
}

Array<T> :: operator [] () will be determined by the Array to which the subscripting operation is applied.
Array<int> v1(20);
Array<dcomplex> v2(30);
v1[3] = 7; // Array<int>::operator[]()
v2[3] = dcomplex(7,8); // Array<dcomplex>::operator[]()

int main() {
  std::cout<< msg << std::endl;
  return EXIT_SUCCESS;
}

$ ./cppgl17.sh p359
$ clang++ p359.cpp
p359.cpp:25:7: error: use of undeclared identifier 'T'
Array<T> :: operator [] () will be determined by the Array to which the subscripting operation is applied.
      ^
p359.cpp:25:28: error: expected function body after function declarator
Array<T> :: operator [] () will be determined by the Array to which the subscripting operation is applied.
                           ^
p359.cpp:27:7: error: use of undeclared identifier 'dcomplex'; did you mean '_Complex'?
Array<dcomplex> v2(30);
      ^~~~~~~~
      _Complex
p359.cpp:27:7: warning: plain '_Complex' requires a type specifier; assuming '_Complex double'
Array<dcomplex> v2(30);
      ^
               double
p359.cpp:28:1: error: C++ requires a type specifier for all declarations
v1[3] = 7; // Array<int>::operator[]()
^
p359.cpp:29:1: error: C++ requires a type specifier for all declarations
v2[3] = dcomplex(7,8); // Array<dcomplex>::operator[]()
^
p359.cpp:29:9: error: use of undeclared identifier 'dcomplex'
v2[3] = dcomplex(7,8); // Array<dcomplex>::operator[]()
        ^
1 warning and 6 errors generated.

$ g++-7 p359.cpp
p359.cpp:25:7: error: 'T' was not declared in this scope
 Array<T> :: operator [] () will be determined by the Array to which the subscripting operation is applied.
       ^
p359.cpp:25:8: error: template argument 1 is invalid
 Array<T> :: operator [] () will be determined by the Array to which the subscripting operation is applied.
        ^
p359.cpp:25:28: error: expected constructor, destructor, or type conversion before 'will'
 Array<T> :: operator [] () will be determined by the Array to which the subscripting operation is applied.
                            ^~~~
p359.cpp:27:7: error: 'dcomplex' was not declared in this scope
 Array<dcomplex> v2(30);
       ^~~~~~~~
p359.cpp:27:7: note: suggested alternative: 'double'
 Array<dcomplex> v2(30);
       ^~~~~~~~
       double
p359.cpp:27:15: error: template argument 1 is invalid
 Array<dcomplex> v2(30);
               ^
p359.cpp:28:1: error: 'v1' does not name a type; did you mean 'v2'?
 v1[3] = 7; // Array<int>::operator[]()
 ^~
 v2
p359.cpp:29:1: error: 'v2' does not name a type
 v2[3] = dcomplex(7,8); // Array<dcomplex>::operator[]()
 ^~

#!/bin/bash
astyle -s2 -c < $1.cpp > $1s2.cpp
cat $1s2.cpp