好的，我正在编写一个程序，它使用了几个不同的类，包括一个Linked Sorted List和一个Binary Search Tree / Node类。当我在Visual Studio中编译时，它运行时没有任何投诉，100％顺利，我已经完全调试它，没有错误。但是，当我把它放入Unix时，我必须将它打开，然后用g ++进行测试，一切都会变成地狱。如果我尝试访问超过二叉树的根，我会得到“分段错误”。
当我使用命令“g ++ main.cpp”时，我看到其他类的成员函数的许多“未定义的引用”。现在，我确实拥有所有必要的#include语句，以及使用“#ifndef / #define / #endif”语句。给我问题的唯一两个类是Employee和SearchTreeNode类。以下是这两个以及主要内容：
#include "LinkedSortedList.h"
#include "LinkedNode.h"
#include "Employee.h"
#include "SearchTreeNode.h"
#include <string>
#include <ostream>
#include <iostream>
#include <fstream>
using namespace std;
int main() {
LinkedSortedList<Employee> mylist; //create the LSL
SearchTree mytree; //create the BST
int searchCount = 0; //occasionally used to count recursive calls to function
bool _continue = true;
char command;
do{
cout << "\nEnter your command: \n" << endl;
cout << "(I)nsert\n(F)ind Employee from ID\n(D)elete Employee from ID\n(L)ast Name Search\n(S)ave to file\n(R)ead from file\n(Q)uit" << endl;
cin >> command;
if(command == 'I' || command == 'i'){
//insert
Employee* newEmployee = new Employee();
newEmployee->create();
mylist.insert(*newEmployee);
mytree.insert(newEmployee);
cout << "Employee Added\n----------\n" << endl;
newEmployee->print();
cout << "\n----------\n" << endl;
}
else if(command == 'L' || command == 'l'){
//arbitrary pointer to undefined matches to be used in fetchAllMatches()
LinkedSortedList<Employee>* matches;
string name;
cout << "Last Name to Search for: " << endl;
cin >> name;
Employee* search = new Employee();
search->setLastName(name);
int matchCount = mylist.fetchAllMatches(*search, matches, matchCount);
cout << mylist.size() << " Records Searched.\n"<< matchCount << " Matches Found:" << endl;
//Make sure that there is something to print to avoid errors
if(matchCount > 0)
matches->print();
}
else if(command == 'D' || command == 'd'){
int IDnumber;
cout << "Enter Employee ID to delete: " << endl;
cin >> IDnumber;
if(mytree.getRoot() != NULL) { // make sure there is a tree to search through
Employee *x = mytree.find(IDnumber, searchCount, mytree.getRoot());
if(x->getAddress() != "null"){
mylist.remove(*x);
mytree.remove(x->getId());
cout << "\n" << x << "\n---------\n" << "File Deleted" << endl;
}
} else {
cout << "Tree is empty" << endl;
}
}
else if(command == 'F' || command == 'f'){
int IDnumber;
cout << "Enter Employee ID to find: " << endl;
cin >> IDnumber;
searchCount = 0;
if(mytree.getRoot() != NULL) { // make sure there is a tree to search through
Employee* x = mytree.find(IDnumber, searchCount, mytree.getRoot());
if(x->getAddress() != "null"){
cout << "\n" << *x << "\n" << endl;
} else {
cout << "Employee not found!" << endl;
}
} else {
cout << "Tree is empty" << endl;
}
}
else if(command == 'S' || command == 's'){
string file;
cout << "Write Database to File Name: " << endl;
cin >> file;
mylist.printToFile(file, mylist);
}
else if(command == 'T' || command == 't'){
mytree.print(mytree.getRoot());
}
else if(command == 'R' || command == 'r'){
//read
if(mylist.size() > 0) {
mylist.clear();
mytree.clearTree(mytree);
}
string line;
string file;
int intLine;
cout << "File Name: " << endl;
cin >> file;
ifstream myfile(file.c_str());
if (myfile.is_open())
{
getline (myfile,line);
if(line != "<Records>"){
cout << "Not a database file." << endl;
}
//make sure it's still ok
while ( myfile.good() )
{
getline(myfile, line);
if(line != "<END>"){
Employee* newEmployee = new Employee();
for(int i = 0; i < 10; i++){
switch (i){
case 0:
newEmployee->setLastName(line);
break;
case 1:
getline(myfile, line);
newEmployee->setFirstName(line);
break;
case 2:
myfile >> intLine;
newEmployee->setId(intLine);
break;
case 3:
myfile >> intLine;
myfile.get();
newEmployee->setSalary(intLine);
break;
case 4:
getline(myfile, line);
newEmployee->setDept(line);
break;
case 5:
getline(myfile, line);
newEmployee->setPhone(line);
break;
case 6:
getline(myfile, line);
newEmployee->setAddress(line);
break;
case 7:
getline(myfile, line);
newEmployee->setHireDate(line);
break;
case 8:
getline(myfile, line);
newEmployee->setEmail(line);
break;
case 9:
getline(myfile, line);//eat the dashes
break;
}
}
mylist.insert(*newEmployee);
mytree.insert(newEmployee);
}
else {
myfile.close();
}
}
}
else cout << "Unable to open file";
}
else if(command == 'Q' || command == 'q'){
return 0;
}
else if(command == 'P' || command == 'p'){
mylist.print();
}
}
while(_continue);
return 0;
}
#include <iostream>
using namespace std;
#ifndef _EmployeeClass_
#define _EmployeeClass_
class Employee {
public:
Employee(){
firstName;
lastName;
department;
email;
dateHired;
phoneNumber;
homeAddress;
employeeID = 0;
salary = 0;
//this->create();
}
Employee(string last, string first, int ID, int _salary, string dept, string phone,
string address, string hireDate, string _email){
lastName = last;
firstName = first;
employeeID = ID;
salary = _salary;
department = dept;
phoneNumber = phone;
homeAddress = address;
dateHired = hireDate;
email = _email;
employeeCount++;
}
void create();
//list of getter functions to return private variables, preventing direct access.
int getId();
int getSalary();
string getFirstName();
string getLastName();
string getDept();
string getHireDate();
string getEmail();
string getAddress();
string getPhone();
friend bool operator!= (Employee &x, Employee &y);
friend bool operator== (Employee &x, Employee &y);
friend bool operator<= (Employee &x, Employee &y);
friend bool operator>= (Employee &x, Employee &y);
friend bool operator< (Employee &x, Employee &y);
friend bool operator> (Employee &x, Employee &y);
friend ostream& operator<<(ostream& output, Employee& x);
void print();
//list of setter functions to set values for the private variables, without allowing direct access.
void setPhone(string phone);
void setId(int ID);
void setSalary(int salary);
void setFirstName(string name);
void setLastName(string surname);
void setDept(string dept);
void setHireDate(string hireDate);
void setEmail(string email);
void setAddress(string address);
private:
//private member variables dependant on input for each individual object
string firstName;
string lastName;
string department;
string email;
string dateHired;
string homeAddress;
string phoneNumber;
int employeeID;
int salary;
int employeeCount;
};
#endif
这是员工类：
#include <iostream>
#include "Employee.h"
#ifndef _SearchTreeNodeClass_
#define _SearchTreeNodeClass_
//this class makes a binary search tree of "search tree nodes" which contain 3 pointers:
//left: points to left child (value always less than node)
//right: points to right child (value always greater than node)
//data: points to an Employee object in memory.
using namespace std;
class SearchTreeNode
{
private:
SearchTreeNode( Employee* D,SearchTreeNode* L = NULL, SearchTreeNode* R = NULL ) // constructor
{
data = D;
left = L;
right = R;
};
int count;
Employee* data; // node data
SearchTreeNode* left; // pointer to the left subSearchTree
SearchTreeNode* right; // pointer to the right subSearchTree
friend class SearchTree; // give SearchTree complete access
};
#endif
#ifndef _SearchTreeClass_
#define _SearchTreeClass_
using namespace std;
class SearchTree
{
public:
SearchTree();
virtual ~SearchTree();
SearchTree( const SearchTree& );
SearchTree& operator=( SearchTree& );
SearchTreeNode* getRoot();
SearchTreeNode* find(int, SearchTreeNode*);
Employee* find(int, int, SearchTreeNode* );
void insert( Employee* );
void print();
void destroy( SearchTreeNode* );
void print( SearchTreeNode* );
void clearTree( SearchTree& );
void inorder( SearchTreeNode* );
void remove( int x );
private:
SearchTreeNode* root; // pointer to the root of the search SearchTree
SearchTreeNode* copy( SearchTreeNode* );
void insert( SearchTreeNode*& root, Employee* );
};
#endif
答案 0 :(得分：0)
您遇到的问题有很多可能的原因。我想到的是，在Visual Studio中编译时，您已设置了包含路径 - 搜索头文件的路径。您也可能没有在Visual Studio中设置它，但是当您创建项目并从各个目录向项目添加文件时，VS会默默地为您设置它。
使用g ++，您必须自己提供包含目录。 （如果您在Linux下使用了类似于Visual Studio的IDE，那么这些包含的目录就已经为您设置了。所以，问题不在于Windows和Linux之间的区别，而是在IDE内部开发之间做了很多事情幕后使用命令行进行编译。）
查看g ++的手册页。在链接期间查看用于添加包含目录的-I选项和用于库搜索的-l。 （很可能你需要-I选项。）
鉴于您在Windows上取得了成功，我怀疑您的源代码存在问题。唯一的另一种可能性是你使用了一个特定于Visual Studio的库函数，这在g ++中是不存在的。
答案 1 :(得分：0)
分段错误错误。这可能有很多原因 - 例如，查看here。
当您无法链接所需的库和/或目标文件时，会发生 未定义的引用错误。从简单地使用g++ main.cpp开始，您既没有指定其他源文件，也没有指定任何必需的链接库。
就像上面提到的@Ray一样，当直接在命令行上编译时，你必须自己提供包含和链接目录，这就是我们通常有一个Makefile的原因。使用正确制作的Makefile比直接调用编译器更好，因为 make 检查哪些源文件发生了变化，调用编译器只重建所需的文件而不是所有文件（这对你的项目来说有很大帮助）很大！）。
如果您对Makefile没有太多经验，我建议您使用CMake。它是一个构建系统，为您制作makefile。好的甚至是多平台，所以使用相同的 CMakeLists.txt 文件，您可以为Windows或Linux生成makefile，语法非常简单。
如果您告诉我您拥有的所有源文件以及您可能使用的最终库我可以为您提供一个准确的 CMakeLists.txt 示例，该示例应该为您编译所有内容，但它可以是简单的如下所示（根据您的包含，我假设您的源文件将是 main.cpp ， LinkedSortedList.cpp ， LinkedNode.cpp ，< em> Employee.cpp 和 SearchTreeNode.cpp ）：
cmake_minimum_required (VERSION 2.6)
project (employee_manager CXX)
set (SOURCES
main.cpp
LinkedSortedList.cpp
LinkedNode.cpp
Employee.cpp
SearchTreeNode.cpp
)
add_executable (employee_manager ${SOURCES})
您应该在源代码目录中创建此文件。要将编译输出与源分开，您可以创建一个构建目录，在那里引用CMake，引用父目录中的 CMakeLists.txt 文件，它将为您构建Makefile。从那里，您只需要调用常规的 make 来构建您的程序：
mkdir build
cd build
cmake ..
make
这会将可执行文件 employee_manager 提供给构建目录。