Still new to the world of C++, and the following question is because of a homework assignment! I have not found much in the way of help searching through previously answered questions or Google, does not mean I have not missed it.
The Homework's Goals: 1.) Take user input information and store it in a binary file. 2.) Read that data back in later.
I have an array of up to 10 structures, the struct takes on char array of a user name, char array of user phone number, and a float salary. When I enter a few test cases, the file writes, I am assuming correctly. When I go to read the values in, the first name prints out nicely as does the first phone number. The float gives me -4013602080 not matter what value I had entered into the test case. From there it goes downhill. I am trying this using . My question boils down to two parts, am I "properly" writing the structure members to the file, and how do I read in floats from binary? (or should would it be advantageous to use fopen and fclose?) Hints or references would be wonderful.
header
//my header
#ifndef USERS_H
#define USERS_H
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <limits>
#include <iomanip>
const int arsize=20;
using namespace std;
struct emp
{
char name[arsize];
char phone[arsize];
float salary;
};
class Users
{
private:
//const int arsize=20;
int choice, num_of_names;
public:
Users();
void menu();
void enter(emp*pt, int n);
void print_all(emp*pt);
void print_condition(emp*pt);
void end_phone_array(emp*pt);
void bubble_sort(emp*pt);
void selection_sort(emp*pt);
void raise(emp*pt);
void file_store(emp*pt);
void file_read(emp*pt);
};
#endif USERS_H_
Here is the necessary parts from the source file I believe:
void Users::enter(emp*pt, int n)
{
extern int gl,count,f;
if(gl+n>10)
{
cout<<"Memory Full!\n";
}
else
{
for (int i=count;i<f+n;i++)
{
gl++;
cout<<"Enter user #"<<i+1<< " name(no more than 20 characters)\n";
cin.get();
cin.getline(pt[i].name, arsize);//.get();
cout<<"Enter user #"<<i+1<< " phone #\n";
cin.getline(pt[i].phone, arsize);//.get();
cout<<"Enter user #"<<i+1<< " salary\n";
(cin>>pt[i].salary);//.get();
}
count=gl;
f=gl;
}
}
void Users::file_store(emp* pt)
{
//ifstream::pos_type size;
extern int gl;
//float test;
//ofstream Testfile ("C:\\Users\\Ian\\Desktop\\Programming\\C++\\data.bin", ios::out| ios::binary); //for personal computer use
ofstream Testfile ("data.bin", ios::out | ios::binary);
for (int i=0; i<gl;i++)
{
Testfile.write((char*)&pt[i].name, sizeof(pt));
Testfile.write(pt[i].phone, sizeof(pt[i].phone));
Testfile.write((char *)&pt[i].salary, sizeof(pt[i].salary));
}
}
void Users::file_read(emp*pt)
{
//extern int gl;
struct TEST
{
char n_array[20];
char p_array[13];
float salary;
};
TEST test[20];
for (int i=0;i<20;i++)
{
test[i].n_array[0]='\0';
test[i].p_array[0]='\0';
test[i].salary=0.0;
}
/*ifstream::pos_type size;
* char *memblocktest;*/
ifstream test_in ("data.bin", ios::in | ios::binary);
for(int i=0;i<10;i++)
{
if(test_in.is_open())for(int i=0;i<10;i++)
{
test_in.read((char*)&test, sizeof(test));
cout<<test[i].n_array<<"\n";
cout<<test[i].p_array<<endl;
cout<<"$"<<test[i].salary<<endl;
}
else
cout<<"Don't know what I am doing!\n";
}
}
and here is the main file
#include "stdafx.h"
#include "users.h"
#include <iostream>
#include <cctype>
#include <limits>
#include <iomanip>
#include <cstring>
using namespace std;
extern int gl=0, count =0, f=0;
int main()
{
Users Test;
std::cout.setf(std::ios::fixed);
std::cout.precision(2);
emp*test=new emp[10];
Test.menu();
int choice, num_of_names;
while(1)
{
if(!(cin>>choice))
{
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n');
cout<<"ERROR!\n";
}
else
break;
}
while(choice!=9)
{
switch(choice)
{
case 1:{cout<<"How many users will you enter?\n";
cin>>num_of_names;
Test.enter(test, num_of_names);
Test.end_phone_array(test);
break;}
case 2:{Test.print_all(test);
break;}
case 3:{Test.print_condition(test);
break;}
case 4:{Test.bubble_sort(test);
break;}
case 5:{Test.selection_sort(test);
break;}
case 6:{Test.raise(test);
break;}
case 7:{Test.file_store(test);
break;}
case 8:{Test.file_read(test);
break;}
default:{"Bad Choice..........\n";
break;}
}
Test.menu();
while(1)
{
if(!(cin>>choice))
{
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(),'\n');
cout<<"ERROR!\n";
}
else
break;
}
}
delete [] test;
//system("Pause");
return 0;
}
I imagine there are many things I could improve, but for now I would like to figure binary part out. Any hints are much appreciated. Thanks!
