c++ - 在 OSX 终端 : Undefined symbols for architecture x86_64 中编译 C++

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我正在为一个类项目编写代码，我在 Xcode 中完成了这一切，效果很好。我能够在 Xcode 中编译 w/参数并获得输出。但是，当我尝试在终端中编译它时，我不断收到此错误(我也不确定我是否正确编译它):

francis-mbp:CS280-Assignment1 fren$ gcc /Users/fren/Desktop/CS280-Assignment1/main.cpp -o main 
/Users/fren/Desktop/CS280-Assignment1/main.cpp:31:32: warning: in-class initialization of non-static data member is a C++11 extension [-Wc++11-extensions]
    list<string>::iterator iter=lineToPrint.begin();
                               ^
/Users/fren/Desktop/CS280-Assignment1/main.cpp:32:19: warning: in-class initialization of non-static data member is a C++11 extension [-Wc++11-extensions]
    int charLimit = 60;
                  ^
2 warnings generated.
Undefined symbols for architecture x86_64:
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::compare(char const*) const", referenced from:
      _main in main-b9d962.o
  "std::__1::locale::has_facet(std::__1::locale::id&) const", referenced from:
      std::__1::basic_filebuf<char, std::__1::char_traits<char> >::basic_filebuf() in main-b9d962.o
  "std::__1::locale::use_facet(std::__1::locale::id&) const", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::endl<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&) in main-b9d962.o
      std::__1::basic_filebuf<char, std::__1::char_traits<char> >::imbue(std::__1::locale const&) in main-b9d962.o
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long) in main-b9d962.o
      std::__1::basic_filebuf<char, std::__1::char_traits<char> >::basic_filebuf() in main-b9d962.o
  "std::__1::ios_base::getloc() const", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::endl<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&) in main-b9d962.o
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long) in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::erase(unsigned long, unsigned long)", referenced from:
      Line::addWord(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__init(char const*, unsigned long)", referenced from:
      Line::addWord(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) in main-b9d962.o
      Line::printLine(int) in main-b9d962.o
      _main in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__init(char const*, unsigned long, unsigned long)", referenced from:
      std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > std::__1::operator+<char, std::__1::char_traits<char>, std::__1::allocator<char> >(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, char const*) in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__init(unsigned long, char)", referenced from:
      std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> > std::__1::__pad_and_output<char, std::__1::char_traits<char> >(std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> >, char const*, char const*, char const*, std::__1::ios_base&, char) in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::append(char const*, unsigned long)", referenced from:
      std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > std::__1::operator+<char, std::__1::char_traits<char>, std::__1::allocator<char> >(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, char const*) in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::assign(char const*)", referenced from:
      Line::addWord(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) in main-b9d962.o
      _main in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::push_back(char)", referenced from:
      _main in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
      Line::addWord(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) in main-b9d962.o
      std::__1::list<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >::push_back(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) in main-b9d962.o
      std::__1::list<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >::insert(std::__1::__list_const_iterator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, void*>, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) in main-b9d962.o
      Line::checkBack() in main-b9d962.o
      _main in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, unsigned long, unsigned long, std::__1::allocator<char> const&)", referenced from:
      Line::addWord(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) in main-b9d962.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::~basic_string()", referenced from:
      Line::addWord(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) in main-b9d962.o
      std::__1::list<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >::pop_back() in main-b9d962.o
      std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > std::__1::operator+<char, std::__1::char_traits<char>, std::__1::allocator<char> >(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, char const*) in main-b9d962.o
      Line::printLine(int) in main-b9d962.o
      std::__1::list<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >::pop_front() in main-b9d962.o

      std::__1::list<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >::push_back(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) in main-b9d962.o
      std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > std::__1::operator+<char, std::__1::char_traits<char>, std::__1::allocator<char> >(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, char const*) in main-b9d962.o
      std::__1::list<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >::insert(std::__1::__list_const_iterator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, void*>, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) in main-b9d962.o
      Line::printLine(int) in main-b9d962.o
      Line::popBack(int) in main-b9d962.o
      ...
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
francis-mbp:CS280-Assignment1 fren$ 

这是我的项目的代码(不包括字符限制的主要 bc):

#include <iostream>
#include<string>
#include<vector>
#include<sstream>
#include<fstream>
#include<algorithm>
#include<queue>
#include<list>
#include<iterator>
#include<ctype.h>
using namespace std;


/*
 Class defining data structure that holds linked list containing words to be output
 Contains words on a per-line basis (Empties after each line is printed)
 Handles list operations
 */
class Line
{
public:
    list<string> lineToPrint;
    list<string>::iterator iter=lineToPrint.begin();
    int charLimit = 60;
    string spaceToInsert;

    int totalChars;
    int totalSpaces;
    int numWords;
    int placesForSpaces;
    int spacePerPlace;
    int extraSpaces;

    void addWord (string word);
    void reset (void);
    void changeLimit (int newLimit);
    void printLine (int endOfParagraph);
    void calculateSpaces(void);
    void newParagraph(void);
    void popBack(int type);
    string checkBack(void);
};

void Line::addWord(string word) {

    cout << "adding word: " << word << endl;
    string firstHalfWord;
    string secondHalfWord;
    int numToTruncate;
    int splittingWord = 1;
    lineToPrint.push_back(word);
    totalChars += word.length();
    numWords ++;
    calculateSpaces();
    if(((totalChars > charLimit) && (numWords >= 1)) || ((totalSpaces < placesForSpaces) && (spacePerPlace == 0))) {
        splittingWord = 0;
        lineToPrint.pop_back();
        numToTruncate = totalChars - (charLimit - placesForSpaces - 1);
        if(numToTruncate > word.length()) {
            cout << numToTruncate << " " << word.length();
            cout << "error" << endl;
        } else {
            secondHalfWord = word.substr(word.length() - numToTruncate);
            firstHalfWord = word.erase(word.length() - numToTruncate) + "-";
        }
        lineToPrint.push_back(firstHalfWord);

        totalChars -= (word.length() + secondHalfWord.length());

        totalChars += firstHalfWord.length();


        calculateSpaces();
    }

    if((spacePerPlace <= 2 && extraSpaces<= placesForSpaces)||(spacePerPlace == 3 && extraSpaces == 0)) {
        if(spacePerPlace == 1){
            spaceToInsert = " ";
        } else if (spacePerPlace == 2) {
            spaceToInsert = "  ";
        } else if (spacePerPlace == 3) {
            spaceToInsert = "   ";
        }

        iter++;
        for(int j = placesForSpaces; j > 0; j--) {
            //cout << "inserting " << spacePerPlace << " spaces!" << endl;
            lineToPrint.insert(iter, spaceToInsert);
            totalSpaces -= spacePerPlace;
            if(extraSpaces != 0){
                lineToPrint.insert(iter, " ");
                totalSpaces --;
                extraSpaces --;
            }
            iter++;
        }
        printLine(1);
    }
    if(splittingWord == 0 && secondHalfWord.length() > charLimit){
        iter = lineToPrint.begin();
        addWord(secondHalfWord);
    } else if (splittingWord == 0 && secondHalfWord.length() <= charLimit) {
        lineToPrint.push_back(secondHalfWord);
        totalChars += secondHalfWord.length();
        numWords ++;
    }
    iter = lineToPrint.begin();
    splittingWord = 1;
}

//Resets the list and variables for calculating spaces to insert
void Line::reset(void) {
    lineToPrint.clear();
    totalChars = 0; totalSpaces = 0; numWords = 0; placesForSpaces = 0;
}

//Changes the variable limit used in space insert calculations
void Line::changeLimit(int newLimit) {
    //cout << "Changing Limit to: " << newLimit << endl;
    charLimit = newLimit;
}

//Makes calculations for variables used in space insertion calculations
void Line::calculateSpaces(void) {
    //cout << "calculating spaces..." << endl;
    totalSpaces = charLimit - totalChars;

    if (numWords == 1 && totalChars >= charLimit) {
        placesForSpaces = 0;
        spacePerPlace = 0;
    } else {
        if(numWords == 1){
            placesForSpaces = 1;
        } else {
            placesForSpaces = numWords - 1;
        }
        spacePerPlace = totalSpaces/placesForSpaces;
        extraSpaces = totalSpaces%placesForSpaces;
    }

    //cout << "totalChars: "<< totalChars <<" totalSpaces: "<< totalSpaces << " numWOrds: " << numWords << " placesFOrSpaces: " << placesForSpaces << " spacePerPlace: " << spacePerPlace << " extraSpaces: " << extraSpaces << endl;

}

//Prints the list (with spaces included)
//Takes int argument; 0 = end of paragraph, 1 = not end of paragraph
void Line::printLine(int endOfParagraph) {
    //p1cout << "character limit: " << charLimit << endl;
    if(endOfParagraph == 1) {
        cout << "printing line NOT end of paragraph" << endl;
        for(list<string>::iterator it = lineToPrint.begin(); it != lineToPrint.end(); it++){
            cout << *it;
            lineToPrint.pop_front();
        }
    } else if (endOfParagraph == 0) {
        iter++;
        cout << "printing line end of paragraph" << endl;

        if (numWords != 1) {
            for(int i = placesForSpaces; i >0; i--) {
                lineToPrint.insert(iter, " ");
                iter++;
            }
        }
        iter = lineToPrint.begin();
        for(list<string>::iterator it = lineToPrint.begin(); it != lineToPrint.end(); it++){
            cout << *it;
            lineToPrint.pop_front();
        }
    }
    cout << endl;
    totalChars = 0; totalSpaces = 0; numWords = 0; placesForSpaces = 0;
}

//Prints a new line to separate paragraphs
void Line::newParagraph(void){
    cout << endl;
}

//Returns the string held in the back of the list
string Line::checkBack(void) {
    return lineToPrint.back();
}

//Removes a string off the back of the list
void Line::popBack(int type) {
    if(type == 1){
        string wordToPop = checkBack();
        cout << "word to pop : " << wordToPop << endl;
        int length = wordToPop.length();
        cout << "length of w2pop : " << length <<endl;
        totalChars -= length;
    }
    //cout << "popping from back: " << checkBack();
    lineToPrint.pop_back();
    numWords --;
}

感谢任何帮助

Answer 1

将编译器命令行更改为

g++ /Users/fren/Desktop/CS280-Assignment1/main.cpp -o main 

问题是 gcc编译 main.cpp正确地作为 c++ 代码(由文件扩展名确定)，但不链接 libstdc++.a默认情况下。因此未定义的引用错误。