我是个c++新手,在遍历对象数组时遇到了困难。对象的形式如下:* 类arr;(在我的例子中:人员 * 人员_列表;)
问题:我不知道如何循环遍历对象数组,我想调用它们上的函数,例如,正如你所看到的,我的代码中有Persons类和函数printPersonsInfo(),我在主文件中有数组声明(array personList),我想能够做一些类似于for(Persons p:个人列表)p.打印个人信息();
尝试了很多种循环,循环失败,数组大小也不成功,到目前为止没有任何效果。代码如下:
主文件:
int main()
{
//reading objects from file into array
Persons * personList = Files::createPersonsArray();
//reading objects from file into array
Auto * autoList = Files::createAutoArray();
return 0;
}
Object类之一(两者几乎相同):
class Persons
{
public:
int id;
string name, surename, phone;
Persons() {
//required empty constructor
}
Persons(int i, string n, string s, string p) {
this->id = i;
this->name = n;
this->surename = s;
this->phone = p;
}
void printPersonInfo() {
cout << endl;
cout << "ID : " << id << endl;
cout << "Name : " << name << endl;
cout << "Surename : " << surename << endl;
cout << "Phone : " << phone << endl;
}
};
h类,在这里我从文件中读取数据并将它们生成数组:
class Files
{
public:
static Persons * createPersonsArray() {
string textLine;
// Read from the text file
ifstream PersonsFile("Persons.txt");
//counter
int count = 0;
//counting records in file
while (getline(PersonsFile, textLine))
count++;
//return to start of file
PersonsFile.clear();
PersonsFile.seekg(0, ios::beg);
//making array of persons
Persons* person_list = new Persons[count];
//total persons found
cout << "Lines of persons :" << count << endl;
int i = 0;
// Use a while loop together with the getline() function to read the file line by line
while (getline(PersonsFile, textLine)) {
//explodes line of person info into parts
auto parts = explode( textLine,'#');
//stoi converts ID from string to int
person_list[i] = Persons(stoi(parts[0]), parts[1], parts[2], parts[3]);
//increased counter
i++;
}
// Close the file
PersonsFile.close();
return person_list;
}
static Auto* createAutoArray() {
string textLine;
// Read from the text file
ifstream AutoFile("Auto.txt");
//counter
int count = 0;
//counting records in file
while (getline(AutoFile, textLine))
count++;
//return to start of file
AutoFile.clear();
AutoFile.seekg(0, ios::beg);
//making array of persons
Auto* auto_list = new Auto[count];
//total persons found
cout << "Lines of autos :" << count << endl;
int i = 0;
// Use a while loop together with the getline() function to read the file line by line
while (getline(AutoFile, textLine)) {
//explodes line of person info into parts
auto parts = explode(textLine, '#');
//stoi converts ID from string to int
auto_list[i] = Auto(stoi(parts[0]), stoi(parts[1]), stoi(parts[2]), parts[3], parts[4], parts[5]);
//increased counter
i++;
}
// Close the file
AutoFile.close();
return auto_list;
}
//explode function
static vector<string> explode(string const& s, char delim)
{
vector<string> result;
istringstream iss(s);
for (string token; getline(iss, token, delim); )
{
result.push_back(move(token));
}
return result;
}
//find owner info based on id
static void findCarOwnerInfo(int id) {
string textLine;
// Read from the text file
ifstream PersonsFile("Persons.txt");
//if file is not empty
if (PersonsFile.peek() != ifstream::traits_type::eof()) {
//counting records in file
while (getline(PersonsFile, textLine)) {
auto parts = explode(textLine, '#');
//if person id matches
if (stoi(parts.at(0)) == id) {
cout << endl;
cout << "(ID:"<<parts.at(0)<<") Owner info ---------" << endl;
cout << "Name : " << parts.at(1) << endl;
cout << "Surename : " << parts.at(2) << endl;
cout << "Phone : " << parts.at(3) << endl;
}
}
}
else {
cout << "error finding persons." << endl;
}
}
};
因为我共享了Persons类并从文件中阅读,所以下面是我如何在Persons.txt中存储信息的:
ID#NAME#SURENAME#PHONE
其思想是读取文件,从中创建对象数组,并将其传递给主类。
我使用C++14,如果这有什么区别的话。
谢谢。
2条答案
按热度按时间h43kikqp1#
你只需要返回一个std::vector而不是一个raw指针。raw指针并不带着它所指向的元素数量(你需要一个额外的参数)。然后你可以像往常一样在vector上迭代。
eblbsuwk2#
循环通过对象数组可以这样完成
或者不确定数组的必要大小
Persons对象“x”的副本将附加到文件中每一行的向量。