Input output with structures

Hello everybody!

This is new area for me. Structures and File I\O.
I need to create structure date that will contain the following elements:

Code:

---


struct date {
  int month;
  int day;
  int year;
}reordDate;

struct date blankDate = {0,0,0};

---

This is the date that is initialized to zero. This structure is nested into the one that is bigger and most crucial here:

Code:

---


struct invent{
        char partId[6+1];
        char partDesc[25+1];
        double unitPrice;
        int quanOnHand;
        int reordPoint;
        int reordQuant;
        struct reordDate;
        int delFlag;
}item;

---

Now, after I have this created I need to copy test data that will be created in text file.

Test data:

Part ID Description Unit Price QOH ROP ROQ

Data goes here.

C program will read this data and populate a struct that meets specifications in invent structure.

This is the part I don't understand:

Code:

---


char ch, lastch = ' ';
char tempLine[40];
char bufferLine[80];

typedef struct{
          char partid [6+1];
          long recoffst;
}INDEX;
INDEX indxpt [100];

---

Why is lastch is declared with the ' ' space character. I understand that tempLine and bufferLine are arrays where read data will be temporary stored. typedef struct with only two elements and partid that is repeated from the first structure. What is the purpose of this structure? Variable for typedef structure is index, and now I have array of structures that is equal to 100 of these. I don't understand typedef structures, is that different than when you declare struct plus tag and elements and variable. I tried to find this answer in the book but it is very confusing.

These structures were declared before main function so that means it is global for whole program. I understand that.

I need to write the structure to a binary file opened in w+ mode:

Code:

---


main()
{
  if((inPut = fopen("part.txt","r"))!= NULL)
    if((outPut = fopen("invent.dat","wb+"))!= NULL)
      if (fgets(bufferLine, 80, inPut)==NULL)
        goodrd = 0;
          else
            puts(bufferLine);
}

---

Here my indentation could be bad, but I don't know which of these are nested.

typedef just allows you to rename something to make it more easy to reference, ie:

typedef unsigned int UINT;

now you can do "UINT blah;" and it will be as though you did unsigned int blah;

> char ch, lastch = ' ';
I've no idea either - they seem surplus to the problem as far as I can tell

Your first step is to read the text file one line at a time, using fgets()
Parse that line for information, storing relevant data in your item variable
There are many ways of doing this, but perhaps sscanf() is the most consise
Write the record stored in item to the output file, using fwrite.


> What is the purpose of this structure?
To create an index of the file you create. Basically, you search the index for a matching part number, and the offset tells you where in the file the actual complete record is. Creating it is pretty easy once you've got the first bit above up and running.

> I don't understand typedef structures
typedef is simply a means of attaching a shorter name to complex declarations - and some of them get really complicated.
In your example, it only saves you one word.
These are equivalent.

Code:

---

typedef struct {
          char partid [6+1];
          long recoffst;
} INDEX;
INDEX indxpt [100];

struct index {
          char partid [6+1];
          long recoffst;
};
struct index indxpt [100];

---

I tried to execute this. My compiler doesn't like it.

Code:

---


#include "stdafx.h"
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <string.h>
#include "C:\Documents and Settings\10111260\My Documents\CrtUtil.h"
FILE *inPut, *outPut;
struct date{
        int month, day, year;}reordDate;
        struct date blankDate = {0,0,0};
struct invent{
        char partId[6+1];
        char partDesc[25+1];
        double unitPrice;
        int quanOnHand;
        int reordPoint;
        int reordQuant;
        struct reordDate;
        int delFlag;
}item;

int i, j, goodrd = 1;
int delFlag;

char ch, lastch = ' ';
char tempLine[40];
char bufferLine[80];

typedef struct{
        char partid [6+1];
        long recoffst;
}INDEX;
INDEX indxpt [100];

main()
{
        if((inPut = fopen("C:\\Documents and Settings\\10111260\\My
Documents\\part.txt","r"))!= NULL)//CHECKING IF I HAVE INPUT FILE
                if((outPut = fopen("C:\\Documents and Settings\\10111260\\My
Documents\\invent.dat","wb+"))!= NULL)//CHECKING IF I HAVE OUTPUT FILE
               
                {if (fgets(bufferLine, 80, inPut)==NULL)//IF GETS = NULL goodrd IS
FALSE
                        goodrd = 0;
                else
                        puts(bufferLine);//ELSE bufferLine = THE LINE READ
               
                while(goodrd)//WHILE goodrd IS TRUE
                        {lastch = ' ';//lastch = NULL
                    reordDate = blankDate;
                        delFlag = 0;//delFlag is set to 0
               
                        for( i = 0, j = 0; lastch != ','; i++, j++)
                                        {sscanf(&bufferLine[i], "%c",&ch);//reading the bufferLine
character by character
                                        if(ch != ',')//if  ch is not equal to ','
                                                tempLine[j] = ch;//the character is send to tempLine
                                                lastch = ch;}//lastch = character read
                                for( j = 0; lastch != ','; j++, i++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                               
                                for( j = 0,; lastch != ','; j++, i++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                                for( j = 0,lastch = NULL; lastch != ','; j++, i++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                                for( j = 0,lastch = NULL; lastch != ','; j++, i++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                                for( j = 0,lastch = NULL; lastch != ','; j++, i++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                               
                        }
                }

                tempLine[j-i] = '\0';//tempLine is set to a NULL or in other words is
clear

                strcpy(item.partId, tempLine);

        fwrite (&item, sizeof(struct invent),1, outPut);

        /*fseek (outPut,0L, SEEK_SET);
       
        fread (&item, sizeof(struct invent,1, inPut);
                while(!feof(outPut))
                        offset = ftell(outPut);
*/
                printf("get character\n");

                getch;
        return 0;
}

---

My compiler pointed at this:

Code:

---


struct invent{
        char partId[6+1];
        char partDesc[25+1];
        double unitPrice;
        int quanOnHand;
        int reordPoint;
        int reordQuant;
        struct reordDate;
        int delFlag;
}item;

---

It says that 'type name' has incomplete type. What is highlighted in red that is where problem is.

Thanks.

Code:

---

struct invent{
        char partId[6+1];
        char partDesc[25+1];
        double unitPrice;
        int quanOnHand;
        int reordPoint;
        int reordQuant;
        struct reordDate variableNameGoesHere;
        int delFlag;
}item;

---

You didn't give your variable a name. Basicly what you did is:

Code:

---

struct foo
{
    int;
};

---

Quzah.

I have another error message on line 27
[Warning] multi-line string literals are deprecated.
I counted the lines and it points at the line between following codes:

Code:

---


char ch, lastch = ' ';
char tempLine[40];
char bufferLine[80];

---

Line 27 is in red. Why it pointed at that line and what this error message means.

Thanks everybody for response.

Hi quzah!

I forgot to tell you how I fixed this problem. I put tag name inside and I think it works fine now. My compiler doesn't point at that spot anymore.

This is what I did:

Code:

---


struct date reordDate;

---

I hope that it is OK.

Quote:

---

Originally Posted by barim

Hi quzah!

I forgot to tell you how I fixed this problem. I put tag name inside and I think it works fine now. My compiler doesn't point at that spot anymore.

This is what I did:

Code:

---


struct date reordDate;

---

I hope that it is OK.

---

That's perfect. That's what it wanted you to do. I assumed that 'recordDate' was the actual name of the structure, and you'd left out the instance name. Apparently you had it the other way around. Same end result though.

Quzah.

Code:

---

if((inPut = fopen("C:\\Documents and Settings\\10111260\\My
Documents\\part.txt","r"))!= NULL)//CHECKING IF I HAVE INPUT FILE
                if((outPut = fopen("C:\\Documents and Settings\\10111260\\My
Documents\\invent.dat","wb+"))!= NULL)//CHECKING IF I HAVE OUTPUT FILE

---

It's actually probably talking about these two lines. See how My is one one line, and Documents is on another? That should all be on one line. Otherwise, you can make the last character in the line a \ and it will recognize that you're trying to continue that string but have basicly run out of line room. Like:

Code:

---

char foo[] = "hello \
world";

printf("%s", foo );

---

Quzah.

Thanks quzah!

I have another error message. I assume it is something about the brackets. This is whole complete code again.

Code:

---


#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <string.h>

FILE *inPut, *outPut;
struct date{
        int month;
    int day;
    int year;}reordDate;
        struct date blankDate = {0,0,0};
struct invent{
        char partId[6+1];
        char partDesc[25+1];
        double unitPrice;
        int quanOnHand;
        int reordPoint;
        int reordQuant;
        struct date reordDate;
        int delFlag;
}item;

int i, j, goodrd = 1;
int delFlag;

char ch, lastch = ' ';
char tempLine[40];
char bufferLine[80];

typedef struct{
        char partid [6+1];
        long recoffst;
}INDEX;
INDEX indxpt [100];

main()
{
        if((inPut = fopen("C:\\Documents and Settings\\My Documents\\part.txt","r"))!= NULL)
                if((outPut = fopen("C:\\Documents and Settings\\My Documents\\invent.dat","wb+"))!= NULL)
               
                {if (fgets(bufferLine, 80, inPut)==NULL)

                        goodrd = 0;
                else
                        puts(bufferLine);
               
                while(goodrd)
                        {lastch = ' ';//lastch = NULL
                    reordDate = blankDate;
                        delFlag = 0;
               
                        for( i = 0, j = 0; lastch != ','; i++, j++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                        if(ch != ',')
                                                tempLine[j] = ch;
                                                lastch = ch;}
                                for( j = 0; lastch != ','; j++, i++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                                                       
                               
                                for( j = 0,; lastch != ','; j++, i++)                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                                for( j = 0,lastch = NULL; lastch != ','; j++, i++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                                for( j = 0,lastch = NULL; lastch != ','; j++, i++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                                for( j = 0,lastch = NULL; lastch != ','; j++, i++)
                                        {sscanf(&bufferLine[i], "%c",&ch);
                                                if(ch != ',')
                                                        tempLine[j] = ch;
                                                        lastch = ch;}
                               
                        }
                }

                tempLine[j-i] = '\0';
clear

                strcpy(item.partId, tempLine);

        fwrite (&item, sizeof(struct invent),1, outPut);

        /*fseek (outPut,0L, SEEK_SET);
       
        fread (&item, sizeof(struct invent,1, inPut);
                while(!feof(outPut))
                        offset = ftell(outPut);
*/
                printf("get character\n");

                getch;
        return 0;
}

---

Error message is:

parse error before ';' token

I highlighted problematic spot in red.

Thanks.

Code:

---

for( j = 0,; lastch != ','; j++, i++)

---

Just reread the line carefully.

Quzah.