Ошибка multiple definition при сборке в QT Creator

//
// This is example code from Chapter 6.7 "Trying the second version" of
// "Software - Principles and Practice using C++" by Bjarne Stroustrup
//
 
/*
    This file is known as calculator02buggy.cpp
 
    I have inserted 0 errors that should cause this not to compile
    I have inserted 3 logic errors that should cause the program to give wrong results
 
    First try to find an remove the bugs without looking in the book.
    If that gets tedious, compare the code to that in the book (or posted source code)
 
    Happy hunting!
 
*/
 
#include "../../std_lib_facilities.h"
 
//------------------------------------------------------------------------------
 
class Token {
public:
    char kind;        // what kind of token
    double value;     // for numbers: a value
    Token(char ch)    // make a Token from a char
        :kind(ch), value(0) { }
    Token(char ch, double val)     // make a Token from a char and a double
        :kind(ch), value(val) { }
};
 
//------------------------------------------------------------------------------
 
class Token_stream {
public:
    Token_stream();   // make a Token_stream that reads from cin
    Token get();      // get a Token (get() is defined elsewhere)
    void putback(Token t);    // put a Token back
private:
    bool full {false};        // is there a Token in the buffer?
    Token buffer;     // here is where we keep a Token put back using putback()
};
 
//------------------------------------------------------------------------------
 
// The constructor just sets full to indicate that the buffer is empty:
Token_stream::Token_stream()
:full(false), buffer(0)    // no Token in buffer
{
}
 
//------------------------------------------------------------------------------
 
// The putback() member function puts its argument back into the Token_stream's buffer:
void Token_stream::putback(Token t)
{
    if (full) error("putback() into a full buffer");
    buffer = t;       // copy t to buffer
    full = true;      // buffer is now full
}
 
//------------------------------------------------------------------------------
 
Token Token_stream::get()
{
    if (full) {       // do we already have a Token ready?
        // remove token from buffer
        full=false;
        return buffer;
    }
 
    char ch;
    cin >> ch;    // note that >> skips whitespace (space, newline, tab, etc.)
 
    switch (ch) {
    case '=':    // for "print"
    case 'x':    // for "quit"
    case '(': case ')': case '+': case '-': case '*': case '/':
        return Token(ch);        // let each character represent itself
    case '.':
    case '0': case '1': case '2': case '3': case '4':
    case '5': case '6': case '7': case '8': case '9':
        {
            cin.putback(ch);         // put digit back into the input stream
            double val;
            cin >> val;              // read a floating-point number
            return Token('8',val);   // let '8' represent "a number"
        }
    default:
        error("Bad token");
    }
}
 
//------------------------------------------------------------------------------
 
Token_stream ts;        // provides get() and putback()
 
//------------------------------------------------------------------------------
 
double expression();    // declaration so that primary() can call expression()
 
//------------------------------------------------------------------------------
 
// deal with numbers and parentheses
double primary()
{
    Token t = ts.get();
    switch (t.kind) {
    case '(':    // handle '(' expression ')'
        {
            double d = expression();
            t = ts.get();
            if (t.kind != ')') error("')' expected");
            return d;
        }
    case '8':            // we use '8' to represent a number
        return t.value;  // return the number's value
    default:
        error("primary expected");
    }
}
 
//------------------------------------------------------------------------------
 
// deal with *, /, and %
double term()
{
    double left = primary();
    Token t = ts.get();        // get the next token from token stream
 
    while(true) {
        switch (t.kind) {
        case '*':
            left *= primary();
            t = ts.get();
        case '/':
            {
                double d = primary();
                if (d == 0) error("divide by zero");
                left /= d;
                t = ts.get();
                break;
            }
        default:
            ts.putback(t);     // put t back into the token stream
            return left;
        }
    }
}
 
//------------------------------------------------------------------------------
 
// deal with + and -
double expression()
{
    double left = term();      // read and evaluate a Term
    Token t = ts.get();        // get the next token from token stream
 
    while(true) {
        switch(t.kind) {
        case '+':
            left += term();    // evaluate Term and add
            t = ts.get();
            break;
        case '-':
            left -= term();    // evaluate Term and subtract
            t = ts.get();
            break;
        default:
            ts.putback(t);     // put t back into the token stream
            return left;       // finally: no more + or -: return the answer
        }
    }
}
 
//------------------------------------------------------------------------------
 
int main()
try
{
    cout << "Добро пожаловать в программу калькулятор!" << endl;
    cout << "Вводите выражения с числами с плавающей точкой." << endl;
    while (cin) {
        Token t = ts.get();
        double val;
 
        if (t.kind == 'x') break; // 'q' for quit
        if (t.kind == '=')        // ';' for "print now"
            cout << "=" << val << '\n';
        else
            ts.putback(t);
        val = expression();
    }
    keep_window_open();
}
catch (exception& e) {
    cerr << "error: " << e.what() << '\n';
    keep_window_open();
    return 1;
}
catch (...) {
    cerr << "Oops: unknown exception!\n";
    keep_window_open();
    return 2;
}
 
//------------------------------------------------------------------------------

/*
   std_lib_facilities.h
*/
 
/*
    simple "Programming: Principles and Practice using C++ (second edition)" course header to
    be used for the first few weeks.
    It provides the most common standard headers (in the global namespace)
    and minimal exception/error support.
 
    Students: please don't try to understand the details of headers just yet.
    All will be explained. This header is primarily used so that you don't have
    to understand every concept all at once.
 
    By Chapter 10, you don't need this file and after Chapter 21, you'll understand it
 
    Revised April 25, 2010: simple_error() added
    
    Revised November 25 2013: remove support for pre-C++11 compilers, use C++11: <chrono>
    Revised November 28 2013: add a few container algorithms
    Revised June 8 2014: added #ifndef to workaround Microsoft C++11 weakness
*/
 
#ifndef H112
#define H112 251113L
 
 
#include<iostream>
#include<iomanip>
#include<fstream>
#include<sstream>
#include<cmath>
#include<cstdlib>
#include<string>
#include<list>
#include <forward_list>
#include<vector>
#include<unordered_map>
#include<algorithm>
#include <array>
#include <regex>
#include<random>
#include<stdexcept>
 
//------------------------------------------------------------------------------
 
 
//------------------------------------------------------------------------------
 
typedef long Unicode;
 
//------------------------------------------------------------------------------
 
using namespace std;
 
template<class T> string to_string(const T& t)
{
    ostringstream os;
    os << t;
    return os.str();
}
 
struct Range_error : out_of_range { // enhanced vector range error reporting
    int index;
    Range_error(int i) :out_of_range("Range error: "+to_string(i)), index(i) { }
};
 
 
// trivially range-checked vector (no iterator checking):
template< class T> struct Vector : public std::vector<T> {
    using size_type = typename std::vector<T>::size_type;
 
#ifdef _MSC_VER
    // microsoft doesn't yet support C++11 inheriting constructors
    Vector() { }
    explicit Vector(size_type n) :std::vector<T>(n) {}
    Vector(size_type n, const T& v) :std::vector<T>(n,v) {}
    template <class I>
    Vector(I first, I last) : std::vector<T>(first, last) {}
    Vector(initializer_list<T> list) : std::vector<T>(list) {}
#else
    using std::vector<T>::vector;   // inheriting constructor
#endif
 
    T& operator[](unsigned int i) // rather than return at(i);
    {
        if (i<0||this->size()<=i) throw Range_error(i);
        return std::vector<T>::operator[](i);
    }
    const T& operator[](unsigned int i) const
    {
        if (i<0||this->size()<=i) throw Range_error(i);
        return std::vector<T>::operator[](i);
    }
};
 
// disgusting macro hack to get a range checked vector:
#define vector Vector
 
// trivially range-checked string (no iterator checking):
struct String : std::string {
    using size_type = std::string::size_type;
//  using string::string;
 
    char& operator[](unsigned int i) // rather than return at(i);
    {
        if (i<0||size()<=i) throw Range_error(i);
        return std::string::operator[](i);
    }
 
    const char& operator[](unsigned int i) const
    {
        if (i<0||size()<=i) throw Range_error(i);
        return std::string::operator[](i);
    }
};
 
 
namespace std {
 
    template<> struct hash<String>
    {
        size_t operator()(const String& s) const
        {
            return hash<std::string>()(s);
        }
    };
 
} // of namespace std
 
 
struct Exit : runtime_error {
    Exit(): runtime_error("Exit") {}
};
 
// error() simply disguises throws:
inline void error(const string& s)
{
    throw runtime_error(s);
}
 
inline void error(const string& s, const string& s2)
{
    error(s+s2);
}
 
inline void error(const string& s, int i)
{
    ostringstream os;
    os << s <<": " << i;
    error(os.str());
}
 
 
template<class T> char* as_bytes(T& i)  // needed for binary I/O
{
    void* addr = &i;    // get the address of the first byte
                        // of memory used to store the object
    return static_cast<char*>(addr); // treat that memory as bytes
}
 
 
inline void keep_window_open()
{
    cin.clear();
    cout << "Please enter a character to exit\n";
    char ch;
    cin >> ch;
    return;
}
 
inline void keep_window_open(string s)
{
    if (s=="") return;
    cin.clear();
    cin.ignore(120,'\n');
    for (;;) {
        cout << "Please enter " << s << " to exit\n";
        string ss;
        while (cin >> ss && ss!=s)
            cout << "Please enter " << s << " to exit\n";
        return;
    }
}
 
 
 
// error function to be used (only) until error() is introduced in Chapter 5:
inline void simple_error(string s)  // write ``error: s and exit program
{
    cerr << "error: " << s << '\n';
    keep_window_open();     // for some Windows environments
    exit(1);
}
 
// make std::min() and std::max() accessible on systems with antisocial macros:
#undef min
#undef max
 
 
// run-time checked narrowing cast (type conversion). See ???.
template<class R, class A> R narrow_cast(const A& a)
{
    R r = R(a);
    if (A(r)!=a) error(string("info loss"));
    return r;
}
 
// random number generators. See 24.7.
 
 
 
inline int randint(int min, int max) { static default_random_engine ran; return uniform_int_distribution<>{min, max}(ran); }
 
inline int randint(int max) { return randint(0, max); }
 
//inline double sqrt(int x) { return sqrt(double(x)); } // to match C++0x
 
// container algorithms. See 21.9.
 
template<typename C>
using Value_type = typename C::value_type;
 
template<typename C>
using Iterator = typename C::iterator;
 
template<typename C>
    // requires Container<C>()
void sort(C& c)
{
    std::sort(c.begin(), c.end());
}
 
template<typename C, typename Pred>
// requires Container<C>() && Binary_Predicate<Value_type<C>>()
void sort(C& c, Pred p)
{
    std::sort(c.begin(), c.end(), p);
}
 
template<typename C, typename Val>
    // requires Container<C>() && Equality_comparable<C,Val>()
Iterator<C> find(C& c, Val v)
{
    return std::find(c.begin(), c.end(), v);
}
 
template<typename C, typename Pred>
// requires Container<C>() && Predicate<Pred,Value_type<C>>()
Iterator<C> find_if(C& c, Pred p)
{
    return std::find_if(c.begin(), c.end(), p);
}
 
#endif //H112

TEMPLATE = app
CONFIG += console c++11
CONFIG -= app_bundle
CONFIG -= qt
 
SOURCES += \
    6_TASK_1_calculator.cpp \
    6_TASK_1_calculator.cpp
 
HEADERS += \
    ../../std_lib_facilities.h
 
DISTFILES += \
    bin/6_TASK_1_calculator