#include iostream
#include cmath
#include fstream
#include cstdlib
#include string
using namespace std;
class Device {//Input and store Device Description and Serial Numbers
protected:
static string serial_number;
static string device_description;
public:
Device() {
serial_number = ("6DCMQ32");
device_description = ("TheDell");
}
Device(string s, string d) {
serial_number = s;
device_description = d;
}
};
string Device::device_description;
string Device::serial_number;
class Test {//Input and store Test Description, recent day, and month;
Calculate the next day
protected:
static string Test_Description;
static int recent_month, recent_day, recent_year, new_month;
static int nmonth, next_month, next_day, next_year, max_day;
public:
Test() {
Test_Description = ("Virtual");
}
static void getMonth() {//Calculates the next/new month
next_month = recent_month + nmonth;
new_month = next_month % 12;
if (next_month >= 12) {
cout << "The next Date: " << new_month << " / ";
}
else {
cout << "The next Date: " << next_month << " / ";
}
}
static void getDay() { //Calculates day of next month
if (new_month == 4 || new_month == 6 || new_month == 9 || new_month == 11) {
max_day = 30;
}
else if (new_month == 2) {
max_day = 29;
}
else {
max_day = 31;
}
if (recent_day > max_day) {
cout << max_day << " / ";
}
else {
cout << recent_day << " / ";
}
}
static void getYear() {// Calculate the year of next month
next_year = recent_year + next_month;
if (next_year >= 12) {
cout << recent_year + (next_month / 12) << endl;
}
else {
cout << next_year << endl;
}
}
static void getDate() {// Collects the output of each element of next date
Test::getMonth(), Test::getDay(), Test::getYear();
}
};
string Test::Test_Description;
int Test::recent_month;
int Test::recent_day;
int Test::recent_year;
int Test::new_month;
int Test::nmonth;
int Test::next_month;
int Test::next_day;
int Test::next_year;
int Test::max_day;
class Lab : public Device, public Test {
protected:
static int n;
public:
friend istream & operator>>(istream & in, Lab & lab) {// Inputs
cout << "Enter Device Desciption and Serial Number: ";
getline(in, device_description);
getline(in, serial_number);
cout << "Enter Test Desciption: ";
getline(in, Test_Description);
cout << "Enter the Number of months: ";
in >> nmonth;
cout << "Enter the Most Recent Date(mm/dd/yyyy): ";
in >> recent_month >> recent_day >> recent_year;
return in;
}
friend ostream & operator<<(ostream & out, Lab & lab) {//Outputs
everything in Device Class
out << Lab::device_description << endl;
out << Lab::serial_number << endl;
out << Lab::Test_Description << endl;
getDate();
return out;
}
static void getN() {
cout << "Enter the number of devices: ";
cin >> n;
}
static void getWrite() {
Lab *obj = new Lab[n];
if (obj == 0) {
cout << "Memory Error";
exit(1);
}
for (int i = 0; i<n; i++) {
cin >> obj[i];
cout << endl;
}
ofstream myfile("Device.txt");
myfile.write((char *)obj, n * sizeof(Lab));
delete[] obj;
}
static void getRead() {
ifstream file2("Device.txt");
Lab *obj2 = new Lab[n];
if (obj2 == 0) {
cout << "Memory Error";
exit(1);
}
file2.read((char *)obj2, n * sizeof(Lab));
for (int i = 0; i < n; i++) {
cout << obj2[i];
cout << endl;
}
delete[] obj2;
}
/*void getSearch(){
}*/
};
int Lab::n;
void main() {
Lab L;
L.getN();
L.getWrite();
L.getRead();
system("pause");
}
当我输入输入时，得到的输出是TheDell 6DCMQ32，虚拟。日期正确无误，唯一的问题是设备说明，序列号和测试设备。
文件i / o读取中操作符<<的问题，该问题在构造函数中输出值
目的：输入序列号输入设备下次测试日期的月数， 设备说明，测试说明，最近日期以及两次测试的月数。最后 如果用户输入序列号和下一个日期，则必须搜索该程序 有效列出设备中的所有内容。
答案 0 :(得分：0)
编写您的应用程序要简短一些，我会尽力给您一些指导。
#include <iostream> // Note the '<' and '>' this is to specify is a language provided include
// More includes with the same issue...
using namespace std; // this is general considered bad=practice see https://stackoverflow.com/a/1452738/8480874 for details
//Input and store Device Description and Serial Numbers
class Device
{ // Notice the white space makes it easier to read...
protected:
//static string serial_number; // declaring this static means _EVERY_ device will have the same serial number
//static string device_description; // same as above
string serialNumber;
string deviceDesc;
public:
Device() : serialNumber("6DCMQ32"), deviceDesc("TheDell")
{
//serial_number = ("6DCMQ32"); // Not the best place for initialization
//device_description = ("TheDell"); // Not the best place for initialization
}
//Device(string s, string d) // you never actually use this
//{
// serial_number = s;
// device_description = d;
//}
};
//string Device::device_description; // This is a sign that you variable will be shared between everyone - not required if you remove the static
//string Device::serial_number; // This is a sign that you variable will be shared between everyone - not required if you remove the static
// This suffers from the same probles as the `class device` above
class Test
{
// Lots of stuff was here just trying to short the answer....
// Mostly has the same culprits mentions for the device
// This is one of the fucntions which gets called when you are trying to "save" the info to a file
static void getMonth(/* ostream & out */) // you need this as a paramater
{
next_month = recent_month + nmonth;
new_month = next_month % 12;
if (next_month >= 12)
{
// This function has no idea is needs to redirect the out put to a file...
// its only outputting to the standard console
cout << "The next Date: " << new_month << " / ";
}
else
{
//cout << "The next Date: " << next_month << " / ";
// using the new parameter in comments
// you can now save to your file
out << /*"The next Date: " <<*/ next_month << " / "; // no I comment out your extra message since you file reading does not look for that
}
}
};
// Again we have the same general misuse of C++ ( please keep learning! hopefully I am point you in the right direction )
class Lab : public Device, public Test
{
protected:
static int n;
public:
friend istream & operator>>(istream & in, Lab & lab)
{
// Inputs
cout << "Enter Device Desciption and Serial Number: ";
getline(in, device_description);
getline(in, serial_number);
cout << "Enter Test Desciption: ";
getline(in, Test_Description);
cout << "Enter the Number of months: ";
in >> nmonth;
cout << "Enter the Most Recent Date(mm/dd/yyyy): ";
in >> recent_month >> recent_day >> recent_year;
return in;
}
friend ostream & operator<<(ostream & out, Lab & lab) {//Outputs
everything in Device Class
out << Lab::device_description << endl;
out << Lab::serial_number << endl;
out << Lab::Test_Description << endl;
// Here you should pass the output pipe
getDate(/* out */);
return out;
}
static void getN() {
cout << "Enter the number of devices: ";
cin >> n;
}
static void getWrite()
{
// there's no real need to be using a pointer or memory allocation
//Lab *obj = new Lab[n];
// you can simply use
Lab obj[n];
//if (obj == 0)
//{
// cout << "Memory Error";
// exit(1);
//}
for (int i = 0; i < n; i++)
{
cin >> obj[i];
cout << endl;
}
ofstream myfile("Device.txt");
//myfile.write((char *)obj, n * sizeof(Lab)); // I've never tried writting an object's memory as a char* to file
// usually I like to generate a human readable output
std::string objBuffer = obj.getSaveBuffer(); // you will need to implement this `getSaveBuffer()` functions
myfile << objBuffer; // This can save lots of different value types for you! see http://www.cplusplus.com/reference/ostream/ostream/operator%3C%3C/
//delete[] obj; // since there is no more new; we dont need a delete!
}
// The logic of what you read suffers the same general issues as the write.
// Also what/how you read is very far from the save so I can't venture into any solutions
// I'm hoping this will kick start you to figuring it out on your own =)
static void getRead() {
ifstream file2("Device.txt");
Lab *obj2 = new Lab[n];
if (obj2 == 0) {
cout << "Memory Error";
exit(1);
}
file2.read((char *)obj2, n * sizeof(Lab));
for (int i = 0; i < n; i++) {
cout << obj2[i];
cout << endl;
}
delete[] obj2;
}
/*void getSearch(){
}*/
};
int Lab::n;
// A program that runs should always return a numeric result indicating success or failure
//void main() {
int main()
{
Lab L; // Since everything in all your classes is static this didnt really add anything
// you done need an object if the object contains nothing
L.getN();
L.getWrite();
L.getRead();
system("pause"); // this is also bad practice, see https://stackoverflow.com/a/1107717/8480874
// I personally like `getchar()` because it's easy and quick
}