分段故障11

Question

我收到段故障11的错误。它将通过printall()命令运行，但在printInvalidEmail命令时似乎失败了。

我还可以输入我创建的其他类。我有大约6个不同的类和这些类的头文件。我正在寻找从哪里开始解决此错误。

/*
* roster.cpp
*
*  Created on: Jan 9, 2019
*      Author: kaylasiemon
*/
#include <string>
#include <iostream>
#include <vector>
#include <sstream>
#include "student.h"
#include "securityStudent.h"
#include "networkStudent.h"
#include "softwareStudent.h"
#include "degree.h"
#include "roster.h"
using namespace std;
roster::roster() {
}
roster::~roster() {
}
void roster::add(string studentID, string firstName, string lastName, string emailAddress, int age, int daysInCourse1, int daysInCourse2, int daysInCourse3, degree d){
int courseDays[] = {daysInCourse1, daysInCourse2, daysInCourse3};
if (d == degree::SECURITY)
classRosterArray[iindex++] = new securityStudent(studentID, firstName, lastName, emailAddress, age, courseDays, d);
if (d == degree::SOFTWARE)
classRosterArray[iindex++] = new softwareStudent(studentID, firstName, lastName, emailAddress, age, courseDays, d);
if (d == degree::NETWORK)
classRosterArray[iindex++] = new networkStudent(studentID, firstName, lastName, emailAddress, age, courseDays, d);
}
void roster::remove(string studentID){
bool removeStudent = false;
for(int i = 0; i < 5; i++){
if (classRosterArray[i] != NULL) {
if(studentID == classRosterArray[i] ->getID()){
classRosterArray[i] = nullptr;
removeStudent = true;
}
}
}
if (removeStudent == false)
cout << "Student ID invalid. No one to remove";
}
void roster::printAll(){
cout << "Roster:" << endl;
for (int i = 1; i < 6; i++)
classRosterArray[i] -> print();
}
void roster::printByDegreeProgram(int degreeProgram){
cout << "Displaying Roster by Degree Type:" << endl;
degree deg1;
if (degreeProgram == 0)
deg1 = degree::SECURITY;
if (degreeProgram == 1)
deg1 = degree::NETWORK;
if (degreeProgram == 2)
deg1 = degree::SOFTWARE;
for (int i = 1; i < 6; i++){
if (deg1 == classRosterArray[i]->getDegreeProgram())
classRosterArray[i] -> print();
}
}
void roster::printDaysInCourse(string studentID){
int average;
for (int i = 1; i < 6; i++){
if (classRosterArray[i] ->getID() == studentID){
average = (classRosterArray[i]->getCourseDays()[0] + classRosterArray[i]->getCourseDays()[1] + classRosterArray[i]->getCourseDays()[2]) / 3;
cout << average << endl;
}
}
}
void roster::printInvalidEmails(){
cout << "invalid email addresses:" << endl;
for (int i = 0; i < 5; i++){
bool atSign = false;
bool space = false;
bool period = false;
string email;
email = classRosterArray[i] ->getemail();
for (char &letter:email){
if (letter == '@')
atSign = true;
if (letter == ' ')
space = true;
if (letter == '.')
period = true;
}
if (atSign == false || space == false || period == false)
cout << classRosterArray[i] ->getemail() << endl;
}
}
int main(){
const string studentData[] ={   "A1,John,Smith,John1989@gm ail.com,20,30,35,40,SECURITY",
"A2,Suzan,Erickson,Erickson_1990@gmailcom,19,50,30,40,NETWORK",
"A3,Jack,Napoli,The_lawyer99yahoo.com,19,20,40,33,SOFTWARE",
"A4,Erin,Black,[e-mail],22,50,58,40,SECURITY",
"A5,Kayla,Siemon,[e-mail],24,30,33,29,SOFTWARE"};
roster classRoster;
cout << "Scripting and Programming - Applications – C867" << endl << "Kayla Siemon" << endl <<"#000736769" << endl;
degree degreepath;
for (int i = 0; i < 5; i++){
stringstream studentlist(studentData[i]);
vector<string> results;
while(studentlist.good()){
string temp;
getline(studentlist, temp, ',');
results.push_back(temp);
}
if (results[8] == "SECURITY")
degreepath = degree::SECURITY;
if (results[8] == "NETWORK")
degreepath = degree::NETWORK;
if (results[8] == "SOFTWARE")
degreepath = degree::SOFTWARE;
classRoster.add(results[0], results[1], results[2], results[3], stoi(results[4]), stoi(results[5]), stoi(results[6]), stoi(results[7]), degreepath);
}
classRoster.printAll();
classRoster.printInvalidEmails();
classRoster.printDaysInCourse("A1");
classRoster.printByDegreeProgram(SOFTWARE);
classRoster.remove("A3");
classRoster.remove("A3");
return 0;
}

Answer 1

这是一个发展调试技能的好机会。您要做的第一件事是准确地计算是哪行代码触发了崩溃。您可以使用调试器(通过逐步执行代码)来实现这一点，或者如果您愿意，您可以手动插入代码。例如，如果您认为崩溃发生在printInvalidEmail()方法中，您可以通过临时向该方法添加调试输出行来将其缩小到特定行，如下所示：

void roster::printInvalidEmails(){
cout << "invalid email addresses:" << endl;
for (int i = 0; i < 5; i++){
cout << "X1 " << i << endl;
bool atSign = false;
bool space = false;
bool period = false;
cout << "X2 " << endl;
string email;
cout << "X3 " << endl;
email = classRosterArray[i] ->getemail();
cout << "X4 " << endl;
for (char &letter:email){
cout << "X5 " << letter << endl;
if (letter == '@')
atSign = true;
if (letter == ' ')
space = true;
if (letter == '.')
period = true;
}
cout << "X6" << endl;
if (atSign == false || space == false || period == false)
{
cout << "X7" << endl;
cout << classRosterArray[i] ->getemail() << endl;
}
cout << "X8" << endl;
}
cout << "X9" << endl;
}

请注意，我插入了很多像cout << "X1" << endl;这样的行，每行都打印一个唯一的字符串，这样我就可以很容易地将它们区分开来。现在，当你运行你的程序时，你会得到更多的输出，但最重要的是你的程序输出的最后一行文本，就在它崩溃之前——导致崩溃的代码可能直接在输出文本的那一行之后。

找到那一行，它会(希望)让你知道这一行可能崩溃的原因——例如，如果你看到的最后一行文本输出是"X3"，而之后你没有看到打印的"X4"，那么你可以非常确定是email = classRosterArray[i]->getemail();行导致了崩溃。。。其中一个可能的原因是classRosterArray[i]是一个NULL或无效指针(因此，当您试图取消引用它来调用getemail()时会发生崩溃)，然后您需要跟踪在classRosterArray中设置条目的各个位置，以找出它们没有正确设置它的原因。(或者，也可能是getmail()方法中有一个错误，程序在里面崩溃了——在这种情况下，你可以在该方法中添加更多的调试输出，以找出原因和位置)

一旦您弄清楚了导致崩溃的原因并修复了它，就可以返回并再次删除所有临时调试输出行。(注意，我故意不缩进所有临时cout调用，这样它们就可以明显地从"真实"代码中突出出来，而且在调试完成后很容易返回并快速删除它们)