通过循环另一个用于搜索文件的函数从文件中打印出信息- c++
Printing out information from a file by looping through another function designed to search the file - C++
我有这样一个函数，它可以扫描我的文件，并根据你选择查看的记录打印出预先指定的记录:
void addressBook::showRecord(int pickNum) {
PEOPLE2 p;
ifstream indata("vectortest.dat", ios::binary);
if(!indata) {
cout << "Error opening file for reading " << endl;
exit(0);
}
indata.seekg(pickNum * sizeof(PEOPLE2));
indata.read(reinterpret_cast <char*> (&p), sizeof(PEOPLE2));
cout << p.fName2 << " " << p.lName2 << " " << p.Address2 << " " << endl;
}
你所要做的就是将showRecord弹出到main中，然后选择你想要打印出来的名字。如果我想查看存储的第二个名字，我可以输入
newBook->showRecord(1);
这一切都很好，它工作完美，但如果我想更进一步呢?因此，我创建了另一个函数，该函数可以使用showRecord打印存储在文件中的地址簿中的所有名称。我试过了:
void addressBook::showAll() {
ifstream indata("vectortest.dat", ios::binary);
for(int i = 0; i < indata.end; i++) {
showRecord(i);
}
}
，它的工作，但它只打印的东西，硬编码到我的PERSON结构从以前的分配:
addressBook *newBook = addressBook::newbookInst();
PERSON me[] = {{"First" , "Last", "ADDRESS"}, {"John", "Doe", "1234"}};
newBook->addPerson(me[1]);
newBook->addPerson(me[0]);
这很奇怪，因为当我进入文件本身时，我可以看到所有添加的名称。
那么我该如何使用它来打印文件中的所有内容，而不仅仅是永久存储的两个条目呢?
这是我的addressbook.h和addressbook.cpp代码，以防你需要更好地了解发生了什么…
addressbook.h////////
#ifndef _ADDRESSBOOK
#define _ADDRESSBOOK
#include <fstream>
#include <vector>
#include<string>
using std::string;
#include <iostream>
using namespace std;
using std::istream;
using std::ostream;
namespace CJ
{
const int MAXADDRESS =25;
struct PERSON
{
string fName;
string lName;
string Address;
};
struct PEOPLE2
{
char fName2[25];
char lName2[25];
char Address2[25];
};
class addressBook
{
private:
vector<PERSON> people;
int head;
int tail;
public:
addressBook();
addressBook(const PERSON &p);
addressBook(const PERSON p[], int size);
addressBook(char *fName, char *lName, char *address);
bool addPerson(const PERSON &p);
bool sortcomp(const PERSON& p1, const PERSON& p2);
bool getPerson(PERSON &p);
bool findPerson(const string& lastName, PERSON& p);
bool findPerson(const string& lastName, const string& firstName, PERSON& p);
void bubbleSort(int *array,int length);
void printBook();
void sort();
void waitKey();
static addressBook *newbookInst();
static addressBook *tempNew;
static PERSON *p();
static PERSON *temPerson;
void showRecord(int pickNum);
void writeRecord();
void showAll();
friend ostream &operator << (ostream &, addressBook &);
addressBook operator =(const string& str);
addressBook &operator +=(const PERSON &p);
addressBook operator [](int x);
};
}
#endif
addressbook.cpp/////
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <conio.h>
#include <string>
using std::string;
#include "addressBook.h"
#include "menu.h"
namespace CJ
{
addressBook::addressBook()
: head(0), tail(-1)
{
}
addressBook::addressBook(const PERSON &p)
: head(0), tail(-1)
{
addPerson(p);
}
addressBook::addressBook(const PERSON p[], int size)
: head(0), tail(-1)
{
for(int i = 0; i < size; i++)
addPerson(p[i]);
}
addressBook::addressBook(char *fName, char *lName, char *Address)
: head(0), tail(-1)
{
PERSON tmp;
tmp.fName = fName;
tmp.lName = lName;
tmp.Address = Address;
addPerson(tmp);
}
bool addressBook::addPerson(const PERSON &p)
{
people.push_back(p);
if(tail == -1)
tail++;
return true;
}
bool addressBook::getPerson(PERSON &p)
{
if(tail >=0)
{
if(tail >= people.size())
tail = 0;
p = people[tail];
tail++;
return true;
}
return false;
}
bool addressBook::findPerson(const string &lastName, PERSON &p)
{
for(size_t i = 0; i < people.size(); i++)
{
if(people[i].lName == lastName)
{
PERSON *p = addressBook::p();
*p = people[i];
return true;
}
}
return false;
}
bool addressBook::findPerson(const string &lastName, const string &firstName, PERSON &p)
{
for(size_t i = 0; i < people.size(); i++)
{
if(people[i].lName == lastName && people[i].fName == firstName)
{
PERSON *p = addressBook::p();
*p = people[i];
return true;
}
}
return false;
}
void addressBook::printBook()
{
for(size_t i = 0; i < people.size(); i++)
{
std::cout << people[i].fName << "t" << people[i].lName << "t" << people[i].Address << std::endl;
}
}
bool addressBook::sortcomp(const PERSON& p1, const PERSON& p2)
{
int result = (p1.lName.compare(p2.lName)) ;
if ( result > 0 )
return true ;
if ( result < 0 )
return false ;
return (p1.fName.compare(p2.fName)) > 0 ;
}
void addressBook::sort()
{
bool didSwap ;
do
{
didSwap = false ;
for ( unsigned i=1; i<people.size(); ++i )
if ( sortcomp(people[i-1], people[i]) )
{
std::swap(people[i-1], people[i]) ;
didSwap = true ;
}
} while ( didSwap ) ;
}
addressBook &addressBook::operator +=(const PERSON &p)
{
addPerson(p);
return *this;
};
addressBook addressBook::operator [](int x)
{
return people[x];
};
ostream &operator << (ostream &output, addressBook &ab)
{
PERSON tmp;
ab.getPerson(tmp);
output << tmp.fName << " " << tmp.lName << " " << tmp.Address << endl;
return output;
}
addressBook * addressBook::tempNew = NULL;
addressBook *addressBook::newbookInst()
{
if(tempNew == NULL)
{
tempNew = new addressBook;
}
return tempNew;
}
PERSON * addressBook::temPerson = NULL;
PERSON *addressBook::p()
{
if(temPerson == NULL)
{
temPerson = new PERSON;
}
return temPerson;
}
bool status;
char lName[50];
char fName[50];
void addressBook::writeRecord()
{
PEOPLE2 temp;
ofstream outFile("vectortest.dat", ios::app);
if(!outFile)
{
cout << "Error opening file for writing " << endl;
return;
}
for (vector<PERSON>::iterator iter = people.begin(), end = people.end(); iter != end; ++iter)
{
strncpy(temp.fName2, iter->fName.c_str(), 25);
strncpy(temp.lName2, iter->lName.c_str(), 25);
strncpy(temp.Address2, iter->Address.c_str(), 25);
outFile.write(reinterpret_cast<const char *>(&temp), sizeof(PEOPLE2));
}
outFile.close();
}
void addressBook::showRecord(int pickNum)
{
PEOPLE2 p;
ifstream indata("vectortest.dat", ios::binary);
if(!indata)
{
cout << "Error opening file for reading " << endl;
exit(0);
}
indata.seekg(pickNum * sizeof(PEOPLE2));
indata.read(reinterpret_cast<char *>(&p), sizeof(PEOPLE2));
cout << p.fName2 << " " << p.lName2 << " " << p.Address2 << " " << endl;
indata.close();
}
void addressBook::showAll()
{
ifstream indata("vectortest.dat", ios::binary);
for(int i = 0; i < indata.end; i ++)
{
showRecord(i);
}
}
}
我真的不太了解你计划如何使用你的地址簿类的上下文。但是我所做的是将你所拥有的基本结构重新制作成更习惯的c++。希望这能对你们今后学习这门课有所帮助。从文件读取的问题，你有问题的修复。
#include <iostream>
#include <iterator>
#include <fstream>
#include <cstdlib>
#include <conio.h>
#include <string>
#include <vector>
#include <algorithm>
const int MAXADDRESS = 25;
struct PEOPLE2
{
char fName2[25];
char lName2[25];
char Address2[25];
};
struct PERSON
{
PERSON()
{}
PERSON(PEOPLE2 p)
: fName(p.fName2), lName(p.lName2), Address(p.Address2)
{}
PERSON(const std::string& first, const std::string& last, const std::string& add)
: fName(first), lName(last), Address(add)
{}
std::string fName;
std::string lName;
std::string Address;
};
// required for std::sort
bool operator< (const PERSON &lhs, const PERSON &rhs)
{
int result = (lhs.lName.compare(rhs.lName));
if(result == 0)
return lhs.fName < rhs.fName;
return result < 0;
}
// required for os << people
std::ostream& operator<< (std::ostream& os, const PERSON& rhs)
{
os << rhs.fName << " " << rhs.lName << " " << rhs.Address;
return os;
}
class addressBook
{
private:
std::vector<PERSON> people;
public:
addressBook()
{ }
addressBook(const PERSON &p)
{
addPerson(p);
}
template<typename IT>
addressBook(IT begin, IT end)
{
std::copy(begin, end, std::back_inserter(people));
}
addressBook(char *fName, char *lName, char *address)
{
PERSON tmp;
tmp.fName = fName;
tmp.lName = lName;
tmp.Address = address;
addPerson(tmp);
}
addressBook(const std::string& fileName)
{
std::ifstream indata(fileName, std::ios::binary);
PEOPLE2 p;
while(true)
{
indata.read(reinterpret_cast<char*>(&p), sizeof(PEOPLE2));
if(indata.fail())
break;
people.push_back(p);
}
}
void addPerson(const PERSON &p)
{
people.push_back(p);
}
bool findPerson(const std::string& lastName, PERSON& p)
{
std::find_if(std::begin(people), std::end(people), [&](const PERSON& in)->bool
{
if(lastName == in.lName)
{
p = in;
return true;
}
return false;
});
}
bool findPerson(const std::string& lastName, const std::string& firstName, PERSON& p)
{
std::find_if(std::begin(people), std::end(people), [&](const PERSON& in)->bool
{
if(lastName == in.lName && firstName == in.fName)
{
p = in;
return true;
}
return false;
});
}
void printBook()
{
std::for_each(std::begin(people), std::end(people), [](const PERSON& p)
{
std::cout << p.fName << "t" << p.lName << "t" << p.Address << std::endl;
});
}
void sort()
{
std::sort(std::begin(people),std::end(people));
}
void waitKey();
void showRecord(int pickNum)
{
std::cout << people[pickNum] << std::endl;
}
void writeRecord(const std::string& fileName)
{
PEOPLE2 temp;
std::ofstream outFile(fileName, std::ios::app);
if(!outFile)
{
std::cout << "Error opening file for writing " << std::endl;
return;
}
for(auto iter = people.begin(), end = people.end(); iter != end; ++iter)
{
strncpy(temp.fName2, iter->fName.c_str(), 25);
strncpy(temp.lName2, iter->lName.c_str(), 25);
strncpy(temp.Address2, iter->Address.c_str(), 25);
outFile.write(reinterpret_cast<const char *>(&temp), sizeof(PEOPLE2));
}
}
void showAll()
{
std::for_each(std::begin(people), std::end(people), [](const PERSON& in)
{
std::cout << in << std::endl;
});
}
friend std::ostream &operator << (std::ostream &output, addressBook &ab)
{
std::for_each(std::begin(ab.people), std::end(ab.people), [&](const PERSON& in)
{
output << in << "n";
});
return output;
}
addressBook &operator +=(const PERSON &p)
{
addPerson(p);
return *this;
};
PERSON operator [](int x)
{
return people[x];
};
};
std::string fileName = "c:\temp\test.rec";
int main()
{
addressBook ab(fileName);
ab.sort();
ab.showAll();
//addressBook ab;
//ab.addPerson(PERSON("Mary", "Smith", "1 West Street"));
//ab.addPerson(PERSON("Joe", "Brown", "2 East Street"));
//ab.addPerson(PERSON("Harry", "Cooper", "3 South Street"));
//ab.writeRecord(fileName);
}
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