Thread: I/O stream files

Code:

#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;

const int MaxHolidays = 25;
const int MaxDescLength = 40;
const char HOLIDAY_FILE[] = "holidays.txt";

struct holidayStruct {
    int holidayId;
    char description[MaxDescLength+1];
    int month;
    int day;
    double cost;
};

holidayStruct *
readHoliday(istream &holidayFile)
{
    int id;
    holidayStruct *holidayPtr;
    
    holidayFile >> id;
    if (!holidayFile.eof()) {
        holidayPtr = new holidayStruct;
        if (!holidayPtr) {
            cerr << "Critical Error: Failure to allocate memory in "
                 << "readHoliday() function.\n"
                 << "Contact your holiday management program team to resolve\n"
                 << "this problem." << endl;
            exit(1);
        } 
        holidayPtr->holidayId = id;
        holidayFile >> holidayPtr->month >> holidayPtr->day >> holidayPtr->cost;
        holidayFile.ignore();
        holidayFile.getline(holidayPtr->description, MaxDescLength+1);
        return (holidayPtr);
    } else return NULL;
}

int
holidays()
{
    holidayStruct *items[MaxHolidays];
    holidayStruct *itemPtr = NULL;

    int i;                // general loop counter
    int itemCount;       // current number of items
    ifstream inputFile;

    inputFile.open(HOLIDAY_FILE, ios::in);
    if (inputFile.fail())
    {
        cerr << "Holiday file " << HOLIDAY_FILE
             << " could not be opened." << endl;
        cin.get();
        exit(1);
    }

    //reading from the file
    itemCount = 0;
    while (itemCount < MaxHolidays
        && (items[itemCount] = readHoliday(inputFile)) )
        ++itemCount;
    cout << itemCount << " holidays read in.\n";
    
    cout << setiosflags(ios::fixed);
    cout.precision(2);

    if (itemCount)
        cout << setw(10) << "id" << setw(10) << "Month"
             << setw(10) << "Day" << setw(12) << "Cost"
             << "  Description\n\n";
             
    for(i=0; i<itemCount; i++)
        cout << setw(10) << items[i]->holidayId
             << setw(10) << items[i]->month
             << setw(10) << items[i]->day
             << setw(12) << items[i]->cost
             << " " << items[i]->description << endl;

    return 0;
}

I'm trying to convert this to C language. Here is what I've done:

Code:

#include <cstdio>
#include <cstdlib>
#include <iomanip>


const int MaxHolidays = 25;
const int MaxDescLength = 40;
const char HOLIDAY_FILE[] = "holidays.txt";

struct holidayStruct {
    int holidayId;
    char description[MaxDescLength+1];
    int month;
    int day;
    double cost;
};

holidayStruct *
readHoliday(FILE *inFile)
{
    int id;
    holidayStruct *holidayPtr;
    
    inFile = fopen ("holidayFile.txt", "r");
    if (inFile!=NULL) {
        holidayPtr = new holidayStruct;
        if (!holidayPtr) {
            printf("Critical Error: Failure to allocate memory in \n");
            printf("readHoliday() function.\n");
            printf("Contact your holiday management program team to resolve\n");
            printf("this problem\n"); 
            exit(1);
        } 
        holidayPtr->holidayId = id;
        
        fscanf(inFile, "%d %d %f" , holidayPtr->month, holidayPtr->day, holidayPtr->cost);
        fclose(inFile);
        fgets(holidayPtr->description, MaxDescLength+1, inFile);
        return (holidayPtr);
    } else return NULL;
}

int
holidays()
{
    holidayStruct *items[MaxHolidays];
    holidayStruct *itemPtr = NULL;

    int i;                // general loop counter
    int itemCount;       // current number of items
    FILE *inputFile;

    inputFile = fopen(HOLIDAY_FILE, "r");
    if (inputFile==NULL)
    {
        cerr << "Holiday file " << HOLIDAY_FILE
             << " could not be opened." << endl;
        cin.get();
        exit(1);
    }

    //reading from the file
    itemCount = 0;
    while (itemCount < MaxHolidays
        && (items[itemCount] = readHoliday(inputFile)) )
        ++itemCount;
    cout << itemCount << " holidays read in.\n";
    
    cout << setiosflags(ios::fixed);
    cout.precision(2);

    if (itemCount)
        cout << setw(10) << "id" << setw(10) << "Month"
             << setw(10) << "Day" << setw(12) << "Cost"
             << "  Description\n\n";
             
    for(i=0; i<itemCount; i++)
        cout << setw(10) << items[i]->holidayId
             << setw(10) << items[i]->month
             << setw(10) << items[i]->day
             << setw(12) << items[i]->cost
             << " " << items[i]->description << endl;

    return 0;
}

Would you guys take a look at this and let me know if something is wrong??
Also what functions can I substitute for "holidayFile.ignore" and holidayFile.eof() to make it work in C?
I really appreciate your help.

holidayPtr = new holidayStruct;
and all the cout <<
just from looking at it quick

I don't see the 2 things your asking about, the .ignore and .eof(), maybe I'm not looking hard enough

well you could use #define for those constants. you never really initialized id. you did holidayPtr->holidayId = id; but I think the compiler will complain. I would suggest flippin it to id=holidayPtr->holidayId; that should work. And (somebody correct me if I'm wrong) you need a & on holidayPtr->cost. If it's a string it doesn't need it, but if it's not....use &. Change all of this:

Code:

 cerr << "Holiday file " << HOLIDAY_FILE
             << " could not be opened." << endl;
        cin.get();

And then just switch all your couts and you should be good!!! Hope that helps and if I'm wrong....it happens often....but I think I'm pretty right on.

Originally Posted by malooch

Code:

#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;

const int MaxHolidays = 25;
const int MaxDescLength = 40;
const char HOLIDAY_FILE[] = "holidays.txt";

struct holidayStruct {
    int holidayId;
    char description[MaxDescLength+1];
    int month;
    int day;
    double cost;
};

holidayStruct *
readHoliday(istream &holidayFile)
{
    int id;
    holidayStruct *holidayPtr;
    
    holidayFile >> id;
    if (!holidayFile.eof()) {
        holidayPtr = new holidayStruct;
        if (!holidayPtr) {
            cerr << "Critical Error: Failure to allocate memory in "
                 << "readHoliday() function.\n"
                 << "Contact your holiday management program team to resolve\n"
                 << "this problem." << endl;
            exit(1);
        } 
        holidayPtr->holidayId = id;
        holidayFile >> holidayPtr->month >> holidayPtr->day >> holidayPtr->cost;
        holidayFile.ignore();
        holidayFile.getline(holidayPtr->description, MaxDescLength+1);
        return (holidayPtr);
    } else return NULL;
}

int
holidays()
{
    holidayStruct *items[MaxHolidays];
    holidayStruct *itemPtr = NULL;

    int i;                // general loop counter
    int itemCount;       // current number of items
    ifstream inputFile;

    inputFile.open(HOLIDAY_FILE, ios::in);
    if (inputFile.fail())
    {
        cerr << "Holiday file " << HOLIDAY_FILE
             << " could not be opened." << endl;
        cin.get();
        exit(1);
    }

    //reading from the file
    itemCount = 0;
    while (itemCount < MaxHolidays
        && (items[itemCount] = readHoliday(inputFile)) )
        ++itemCount;
    cout << itemCount << " holidays read in.\n";
    
    cout << setiosflags(ios::fixed);
    cout.precision(2);

    if (itemCount)
        cout << setw(10) << "id" << setw(10) << "Month"
             << setw(10) << "Day" << setw(12) << "Cost"
             << "  Description\n\n";
             
    for(i=0; i<itemCount; i++)
        cout << setw(10) << items[i]->holidayId
             << setw(10) << items[i]->month
             << setw(10) << items[i]->day
             << setw(12) << items[i]->cost
             << " " << items[i]->description << endl;

    return 0;
}

I'm trying to convert this to C language. Here is what I've done:

Code:

#include <cstdio>
#include <cstdlib>
#include <iomanip>


const int MaxHolidays = 25;
const int MaxDescLength = 40;
const char HOLIDAY_FILE[] = "holidays.txt";

struct holidayStruct {
    int holidayId;
    char description[MaxDescLength+1];
    int month;
    int day;
    double cost;
};

holidayStruct *
readHoliday(FILE *inFile)
{
    int id;
    holidayStruct *holidayPtr;
    
    inFile = fopen ("holidayFile.txt", "r");
    if (inFile!=NULL) {
        holidayPtr = new holidayStruct;
        if (!holidayPtr) {
            printf("Critical Error: Failure to allocate memory in \n");
            printf("readHoliday() function.\n");
            printf("Contact your holiday management program team to resolve\n");
            printf("this problem\n"); 
            exit(1);
        } 
        holidayPtr->holidayId = id;
        
        fscanf(inFile, "%d %d %f" , holidayPtr->month, holidayPtr->day, holidayPtr->cost);
        fclose(inFile);
        fgets(holidayPtr->description, MaxDescLength+1, inFile);
        return (holidayPtr);
    } else return NULL;
}

int
holidays()
{
    holidayStruct *items[MaxHolidays];
    holidayStruct *itemPtr = NULL;

    int i;                // general loop counter
    int itemCount;       // current number of items
    FILE *inputFile;

    inputFile = fopen(HOLIDAY_FILE, "r");
    if (inputFile==NULL)
    {
        cerr << "Holiday file " << HOLIDAY_FILE
             << " could not be opened." << endl;
        cin.get();
        exit(1);
    }

    //reading from the file
    itemCount = 0;
    while (itemCount < MaxHolidays
        && (items[itemCount] = readHoliday(inputFile)) )
        ++itemCount;
    cout << itemCount << " holidays read in.\n";
    
    cout << setiosflags(ios::fixed);
    cout.precision(2);

    if (itemCount)
        cout << setw(10) << "id" << setw(10) << "Month"
             << setw(10) << "Day" << setw(12) << "Cost"
             << "  Description\n\n";
             
    for(i=0; i<itemCount; i++)
        cout << setw(10) << items[i]->holidayId
             << setw(10) << items[i]->month
             << setw(10) << items[i]->day
             << setw(12) << items[i]->cost
             << " " << items[i]->description << endl;

    return 0;
}

Would you guys take a look at this and let me know if something is wrong??
Also what functions can I substitute for "holidayFile.ignore" and holidayFile.eof() to make it work in C?
I really appreciate your help.

Is it me, or did anyone else notice that there is no corresponding call to "delete" in the C++ version, or "free" in the C version? (The C version still uses "new")


:davis: