所以我正在为学校写一个模拟成绩册的大型课程。我已经在这几天了，为什么每当我创建一个新课程时它会随机给我运行时错误。奇怪的是它只是有时候。有时它适用于飞行颜色，有时不适用。错误代码是线程1：EXC_BAD_ACCESS（代码= 1，地址= 0x3002），当我将用户输入分配给课程类数组的成员时，我得到了该错误。代码可能会让我更公平。
这是我将评论频繁出现此错误的行的类的定义。给出错误的主要是在课程类中。
//
// Classes.hpp
// Hw2
//
// Created by Devin Tripp on 2/28/18.
// Copyright © 2018 Devin Tripp. All rights reserved.
//
#include <stdio.h>
#include <stdlib.h>
#include <string>
using namespace std;
#define CHUNKSIZE 2
class Student {
private:
int stud_id;
string name;
public:
void setId(int id) { stud_id = id;}
int getId() { return stud_id;}
void setName(string n) { name = n; } // I recieve an error here sometimes
string getName() { return name;}
};
class Students {
public:
Students() {stud_cnt = 0; stud_cap = CHUNKSIZE; studs = new Student[CHUNKSIZE];}
~Students() { delete [] studs;}
void addStudent();
void printStudents();
int getstud_cap();
Student* getStuds();
void storeStuds();
void loadStuds();
private:
int stud_cnt;
int stud_cap;
Student *studs;
};
class Course {
private:
int course_id;
string course_name;
public:
void setID(int id) {course_id = id;}
int getID() { return course_id;}
void setCourseName(string name) { course_name = name;} // Recieve error here // still getting this error here with new changes
string getCourseName() { return course_name;}
};
class Courses {
public:
Courses() {course_cnt = 0; course_cap = CHUNKSIZE; course_list = new Course[CHUNKSIZE]; for (int i = 0; i < course_cap; i++){
course_list[i].setID(-1);
course_list[i].setCourseName(""); //This still produces the same error
}}
~Courses() { delete [] course_list;}
void addCourse();
void printCourses();
int getCourseCnt() {return course_cnt;}
int getCourseCap() {return course_cap;}
Course *getCourseList() {return course_list;}
void loadCourses();
void storeCourses();
private:
int course_cnt;
int course_cap;
Course *course_list;
};
class Enrollment {
public:
int getEnId() {return en_ID;}
int getCourse_ID() {return course_ID;}
string getCName() {return courseName;}
string getSName() {return studentsNames;}
int getStudID() {return studs_ID;}
void setEnID(int id) { en_ID = id; }
void setCourse_ID(int id) {course_ID = id;}
void setCName(string name) { courseName = name; } // Recieve error here sometimes
void setSname(string name) { studentsNames = name; }
void setStudID(int id) {studs_ID = id;}
void setGrades(int grade, int num) { grades[num] = grade;}
private:
int en_ID;
int course_ID;
string courseName;
int studs_ID;
string studentsNames;
int change_this;
int grades[9];
};
class Enrollments {
public:
Enrollments() {enroll_cnt = 0; enroll_cap = CHUNKSIZE; enroll_list = new Enrollment[CHUNKSIZE];}
~Enrollments() { delete [] enroll_list;}
void addEnrollment(Students s, Student *studs, Courses c, Course *cList);
void printCourseStudent();
void getAverage();
void GetletterGrade();
void addGradesToCourse();
void loadEnrollments();
void saveEnrollments();
private:
int enroll_cnt;
int enroll_cap;
Enrollment *enroll_list;
};
这是类的所有功能。当我添加它们时，存储和加载函数开始引起这些问题，因此它可能是函数中的某些东西。我认为它与字符串有关，因为它只对设置字符串的函数有这个错误。
//
// Classes.cpp
// Hw2
//
// Created by Devin Tripp on 2/28/18.
// Copyright © 2018 Devin Tripp. All rights reserved.
//
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include "Classes.hpp"
#include <fstream>
using namespace std;
int Students::getstud_cap() {
return stud_cap;
}
void Students::addStudent() {
int id;
string temp;
if (stud_cnt == stud_cap) {
Student *temp;
temp = new Student[stud_cap + CHUNKSIZE];
for (int i = 0;i < stud_cnt; i++) {
temp[i] = studs[i];
}
delete [] studs;
stud_cap += CHUNKSIZE;
studs = temp;
}
printf("Enter a new student ID: ");
cin >> id; cin.ignore();
printf("Enter Name: ");
cin >> temp; cin.ignore();
cout << "Got data " << temp << endl;
studs[stud_cnt].setId(id); cout << "Set ID" << endl;
studs[stud_cnt].setName(temp); cout << "Set Name" << endl;
stud_cnt += 1; cout << "inc stud count" << endl;
}
void Students::printStudents() {
for (int i = 0; i < stud_cap; i++) {
cout << studs[i].getName() << " " << studs[i].getId() << endl;
}
}
void Courses::addCourse() {
int id;
string name;
if (course_cnt == course_cap) {
// increase the size of the array
Course *temp;
temp = new Course[course_cap + CHUNKSIZE];
for(int i =0; i < course_cnt; i++){
temp[i] = course_list[i];
}
delete [] course_list;
course_cap += CHUNKSIZE;
course_list = temp;
}
printf("Whats the Course ID?: ");
cin >> id; cin.ignore();
printf("Enter the Name of The Course: ");
cin >> name; cin.ignore();
cout << " Got data " << name << endl;
if (name == "") {
cin >> name;
}
course_list[course_cnt].setID(id);
course_list[course_cnt].setCourseName(name);
course_cnt += 1;
}
void Courses::printCourses() {
for( int i = 0; i < course_cap; i++)
cout << course_list[i].getID() << endl;
}
Student* Students::getStuds(){
return studs;
}
void Enrollments::addEnrollment(Students s, Student *studs, Courses c, Course *cList) {
s.printStudents();
int id;
int courseNum;
int tempI = -1;
int tempITwo = -1;
/*Check if you need to alloc more memory to the array. */
if (enroll_cnt == enroll_cap){
// alloc more space chunksize has been reached
// create temp to hold the previous array
Enrollment *temp;
temp = new Enrollment[enroll_cap + CHUNKSIZE];
for (int i = 0; i < enroll_cap; i++){
temp[i] = enroll_list[i];
}
delete [] enroll_list;
enroll_list += CHUNKSIZE;
enroll_list = temp;
}
/* Find the student and the course */
cout << "Type the students id: " << endl;
cin >> id; cin.ignore();
// loop through to find if the user typed in a number that matches the student id
for (int i = 0; i < s.getstud_cap(); i++) {
if(id == studs[i].getId()) {
//save the i
tempI = i;
}
}
// check if it found the id or if the user typed in a wrong one
if (tempI != -1){
c.printCourses();
cout << "Type the course number: " << endl;
cin >> courseNum; cin.ignore();
// check where in the array the id for the course is
for(int i = 0; i < c.getCourseCap(); i++){
if(courseNum == cList[i].getID()){
tempITwo = i;
}
}
// save the enrollment
if (tempITwo != -1){
enroll_list[enroll_cnt].setCName(cList[tempITwo].getCourseName());
enroll_list[enroll_cnt].setCourse_ID(cList[tempITwo].getID());
enroll_list[enroll_cnt].setSname(studs[tempI].getName());
enroll_list[enroll_cnt].setStudID(studs[tempI].getId());
enroll_list[enroll_cnt].setEnID(studs[tempI].getId() + cList[tempITwo].getID());
} else {
//wrong courseID
cout << "You typed in an invalid course ID" << endl;
}
} else {
//wrong student id
cout << "You typed an invalid Student ID" << endl;
}
enroll_cnt += 1;
}
void Enrollments::printCourseStudent(){
for (int i = 0; i < enroll_cap; i++) {
cout << "Enrollment ID: " << enroll_list[i].getEnId() << " Course: " << enroll_list[i].getCName() << " Course ID: " << enroll_list[i].getCourse_ID() << " Student Name: " << enroll_list[i].getSName() << " Student ID: " << enroll_list[i].getStudID() << endl;
}
}
void Enrollments::addGradesToCourse() {
printCourseStudent();
int id, count = 0, grade, tempI = -1;
cout << "Type the enrollment ID: " << endl;
cin >> id; cin.ignore();
for(int i = 0; i < enroll_cap; i++){
if (id == enroll_list[i].getEnId()) {
tempI = i;
}
}
if (tempI != -1){
for (int i = 0; i < 10; i++){
cout << "Enter grade " << count + 1 << ": ";
cin >> grade; cin.ignore();
enroll_list[tempI].setGrades(grade, count);
count++;
}
}
}
void Courses::loadCourses(){
ifstream fin;
int id;
string name;
fin.open("/Users/devintripp/Desktop/swift projects/Hw2/Hw2/courses.dat");
fin >> course_cnt; fin.ignore();
course_list = new Course[course_cnt];
for ( int i=0; i < course_cnt; i++) {
fin >> id >> name;
course_list[i] .setCourseName(name);
course_list[i].setID(id);
}
fin.close();
}
void Courses::storeCourses() {
ofstream fout;
fout.open("/Users/devintripp/Desktop/swift projects/Hw2/Hw2/courses.dat");
fout << course_cnt << endl;
for ( int i=0; i < course_cnt; i++) {
fout << course_list[i].getID() << " " << course_list[i].getCourseName() << endl;
}
fout.close();
}
void Students::loadStuds(){
ifstream fin;
int id;
string name;
fin.open("/Users/devintripp/Desktop/swift projects/Hw2/Hw2/students.dat");
fin >> stud_cnt; fin.ignore();
studs = new Student[stud_cnt];
for ( int i=0; i < stud_cnt; i++) {
fin >> id >> name;
studs[i].setName(name);
studs[i].setId(id);
}
fin.close();
}
void Students::storeStuds() {
ofstream fout;
fout.open("/Users/devintripp/Desktop/swift projects/Hw2/Hw2/students.dat");
fout << stud_cnt << endl;
for ( int i=0; i < stud_cnt; i++) {
fout << studs[i].getId() << " " << studs[i].getName() << endl;
}
fout.close();
}
void Enrollments::loadEnrollments(){
ifstream fin;
int eid, sid, cid;
string cname, sname;
fin.open("/Users/devintripp/Desktop/swift projects/Hw2/Hw2/enrollments.dat");
fin >> enroll_cnt; fin.ignore();
enroll_list = new Enrollment[enroll_cnt];
for ( int i=0; i < enroll_cnt; i++) {
fin >> eid >> cname >> sname >> sid >> cid;
enroll_list[i].setEnID(eid);
enroll_list[i].setCourse_ID(cid);
enroll_list[i].setCName(cname);
enroll_list[i].setSname(sname);
enroll_list[i].setStudID(sid);
}
fin.close();
}
void Enrollments::saveEnrollments() {
ofstream fout;
fout.open("/Users/devintripp/Desktop/swift projects/Hw2/Hw2/enrollments.dat");
fout << enroll_cnt << endl;
for ( int i=0; i < enroll_cnt; i++) {
fout << enroll_list[i].getEnId() << " " << enroll_list[i].getCourse_ID() << " " << enroll_list[i].getCName() << " " << enroll_list[i].getSName() << " " << enroll_list[i].getStudID();
}
fout.close();
}
最后我有主要方法。它会提示用户输入并运行在classes.cpp中创建的所有函数。
如果您要测试代码，您应该将存储和加载功能更改为您计算机上自己的路径。
//
// Devin Shawn Tripp
// Student ID: 11199100
// CSCE 1040!
// Hw2
//
// Created by Devin Tripp on 2/26/18.
// Copyright © 2018 Devin Tripp. All rights reserved.
//
// notes for tomorrow figure out how to add it to a file that I will create
// 6 classes - main is not a class
#include <sstream>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include "Classes.hpp"
#include <fstream>
using namespace std;
void loadData();
void save();
/* Declare global Objects */
Students stud;
Courses co;
Enrollments e;
int main() {
/* Declare Variables */
int choice = 0;
/* Create Menu */
while (choice != 7) {
loadData();
printf("What do you want to do: \n");
printf("1: Add new Course \n2: Add New Student \n3: Print Students \n4: Save \n5: Add Enrollment \n6: Add Grades to a Course\n7: Quit \n");
cin >> choice;
switch (choice) {
case 1:
// Add a course
co.addCourse();
break;
case 2:
//Add Students
stud.addStudent();
break;
case 3:
// Print students
stud.printStudents();
break;
case 4:
//do something
//stud.save();
break;
case 5:
//do something
e.addEnrollment(stud, stud.getStuds(), co, co.getCourseList());
break;
case 6:
//do something
e.addGradesToCourse();
break;
default:
break;
}
save();
}
return 0;
}
void loadData(){
stud.loadStuds();
co.loadCourses();
e.loadEnrollments();
}
void save() {
stud.storeStuds();
co.storeCourses();
e.saveEnrollments();
}
对象已分配空间，但您尚未调用其构造函数，因此它们尚未初始化，例如：
A* arrayOfAs = new A[5]; //Allocate a block of memory for 5 objects
for (int i = 0; i < 5; ++i)
{
//initialize an object in memory address provided by the pointer
new (&arrayOfAs[i]) A();
}
然而，我会建议你完全避免这种用法，并使用std::vector，因为它包括所有这些，包括阵列放大。
即：
#include <vector>
typedef std::vector<Student*> Students;
Students studs;
// add an item
Student * student = new Student();
studs.push_back(student);
// remove an item
Student * student = studs.pop_front();
delete student;
// iterate the items
for(Students::iterator it = studs.begin(); it != studs.end(); ++it)
{
Student * student = *it;
student->doSomething();
}