Text file - new line issue

Code:

---

if (feof(inSalesPtr) != "\n")
            fprintf(inSalesPtr,"\n");

---

How to design a if statement to achieve the following goal?
1)
Attachment 12146
insert a new line

2)
Attachment 12147
do nothing

Untested:

Code:

---

FILE *inSalesPtr;

//open the file for binary read/append
if ((inSalesPtr = fopen("sales.txt", "a+b")) == NULL) exit(1); /* exit on error */

// set the file position to the very last character
if (fseek(inSalesPtr, -1, SEEK_END)) exit(2); /* exit on error */

// read the last character
int ch = fgetc(inSalesPtr);
if (ch == EOF) exit(3); /* exit on error */

// check if the last character is a '\n'
if (ch != '\n') {
    // if the last character is not a '\n' append a "\r\n" (Windows line break)
    fputs("\r\n", inSalesPtr);
}

// close the FILE
fclose(inSalesPtr);

---

If you pulled in the data using fscanf(), ( or from a buffer, using sscanf() ), then you know you need to add the newline.

So when would you NOT need to enter the newline into the file output?

!feof is a problem - using the return number from fscanf() or sscanf(), like I showed you previously.

Code:

---

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


// number of salesman
#define SIZE 100
// salesman_type structure definition
typedef struct{
                int ID; // salesman id
                char id_txt[6]; // salesman id for txt file
                char name[50]; // salesman name
                double hor_total; // total sales amount of a salesman 
        }salesman_type; // end structure salesman_type


salesman_type salesman[SIZE];// synonym for salesman_type


// function prototype
int nextId(int currentId, int isReset);
int sale_menu();
int report_menu();
void AddSalesMan(int initialId);


// function to generate id
// currentId and isReset are parameters
int nextId(int currentId, int isReset)
{
        // initializes elements to 0 for the first time function is called
        static int lastId = 0;
        // if isReset is 0, assign currentId to lastId;
        if (isReset == 0)
        {
                lastId = currentId;
        }
        //if isReset is not 0, return and add 1 to lastId
        if (isReset != 0)
                return ++lastId;
}
// sales processing system menu function
int sale_menu()
{
        int menu;
        printf("Sales Processing System\n");
        printf("-----------------------\n\n");
        printf("1. Add Salesman Records\n");
        printf("2. Reports Generation\n");
        printf("3. Modify Salesman Records\n");
        printf("4. Delete Salesman Records\n\n");
        printf("0. Exit\n");
        printf("Your choice: ");
        scanf("%d", &menu);
        return menu;
        printf("\n");
}
// reports generation menu function
int report_menu()
{
        int report;
        printf("Reports Generation\n");
        printf("------------------\n\n");
        printf("1. View Quarterly Sales Report\n");
        printf("2. View Individual Salesman Commission\n\n");
        printf("0. Return to Main Menu\n");
        printf("Your choice: ");
        scanf("%d", &report);
        return report;
}
// function to add salesman
void AddSalesMan(int initialId)
{
        // nextid.txt file pointer
        FILE *writeIdPtr;
        // sales.txt file pointer
        FILE *inSalesPtr;
        char ch;
        int a, b; // counter
        int loop = 1; // confirmation
        int creId = 1; // pass value to nextId function to generate ID
        int newId; // receive new generated ID
        double sale[SIZE][4]; // quarterly sales amount


        // fopen opens file; exit program if unable to create file
        if ( (writeIdPtr = fopen("nextid.txt","w") ) == NULL)
        {
                printf("Cannot open nextid.txt.\n"); // display error message
                system("pause"); // pause program before it exits
                exit(-1); // end program
        } //end if
        // fopen opens file; exit program if unable to create file
        if ( (inSalesPtr = fopen("sales.txt","a") ) == NULL)
        {
                printf("Cannot open sales.txt file.\n"); // display error message
                system("pause"); // pause program before it exits
                exit(-1); // end program
        } // end if
        else
        {
                // set the file position to the very last character
                fseek(inSalesPtr, -1, SEEK_END);
                ch = fgetc(inSalesPtr);
                if (ch != '\n')
                {
                        fputs("\r\n",inSalesPtr);
                }
                // write salesname id, quarterly sales amount into file with fprintf       
                for(a=initialId - 1; a<SIZE; a++)
                {
                        // while loop is 1
                        while (loop == 1)
                        {
                                // assign new generated id to newId
                                newId = nextId(initialId, creId);
                                // write newId into file with fprintf
                                fprintf(inSalesPtr,"S%04d|",newId);
                                //printf("Name: ");
                                //scanf(" %[^\n]", salesman[a].name);
                                for (b=0; b<4; b++)
                                {
                                        // prompt and read quarterly sales amount
                                        printf("Quarter %d: ",b+1);
                                        scanf(" %lf", &sale[a][b]);
                                        // write sales[a][b] into file with fprintf
                                        if(b<3)
                                                fprintf(inSalesPtr,"%.2f|",sale[a][b]);
                                        // end if
                                        else
                                                fprintf(inSalesPtr,"%.2f\n",sale[a][b]);
                                        // end else
                                } // end for       
                                printf("\n");
                                printf("Continue?(Yes = 1): "); // prompt user to continue or not
                                scanf("%d",&loop);
                        } // end while
                } // end for
                // write newId into file with fprintf
                fprintf(writeIdPtr,"%d",newId);
                fclose(writeIdPtr); // flose close the file
                fclose(inSalesPtr); // flose close the file
        } // end else
} // end function AddSalesman


// function main begins program execution
void main()
{
        // nextid.txt file pointer
        FILE *readIdPtr;
        // variable declaration
        int a, b, c = 0, last; // counter
        int getMenu = 0, getReport = 0; // menu selector
        double ver_total = 0, max = 0;
        int id = 0, lastId, resetId = 0;


        // fopen opens the file; exits program if file cannot be opened
        if ( (readIdPtr = fopen("nextid.txt","r") ) == NULL)
        {
                printf("Cannot open nextid.txt file\n");
                system("pause");
                exit(-1);
        } // end if
        else
        {
                // read lastId from file
                fscanf(readIdPtr,"%d",&lastId);
                // Generate new id from previous salesman ID if the salesman is one or more
                // lastId and restId are arguments
                nextId(lastId, resetId);
        } // end else
        // fclose close the file
        fclose(readIdPtr);
        // call and assign sale_menu function to getMenu
        getMenu = sale_menu();
        printf("\n");
        // Execute command based on user input
        switch(getMenu)
        {
                // call AddSalesMan function
                case 1:
                        AddSalesMan(lastId);
                        break;
                // call and assign report_menu to getReport
                case 2:
                        break;
        } // end switch
        system("pause"); // pause the program before it exits       
} // end main

---

Why it doesn't work?

WHAT isn't working right?

Describe the problem like you did in the first post of this thread - that was good.

It would be great to know if the advice given since then, has solved that first problem.

Quote:

---

Code:

---

    if ( (inSalesPtr = fopen("sales.txt","a") ) == NULL)
    {
        printf("Cannot open sales.txt file.\n"); // display error message
        system("pause"); // pause program before it exits
        exit(-1); // end program
    } // end if
    else
    {
        // set the file position to the very last character
        fseek(inSalesPtr, -1, SEEK_END);
        ch = fgetc(inSalesPtr);

---

---

You opened the FILE for append mode, but then try to read from it ... this is a big no no: don't do that!
Open the file for reading / appending in binary mode like I suggested

Code:

---

    if ( (inSalesPtr = fopen("sales.txt", "a+b") ) == NULL)

---

Note:
the binary mode may be troublesome (or its absence may be troublesome).

Without binary mode, when a file contains "one\r\ntwo\r\n" (10 characters) it is converted to "one\ntwo\n" (8 characters). Using fseek is not guaranteed to go to the expected place.
With binary mode there is no conversion between what's on disk and what your program sees, so "one\r\ntow\r\n" is effectively read as "one\r\ntwo\r\n" and you have to deal with the '\r's yourself.

My suggestion ,assuming you have to deal with Windows line breaks of "\r\n", is to open the files without the binary flag for normal processing, and open them with the binary flag for precision work within the disk-file itself.

I'm beginning to think that ulti-killer either is a troll or has severe periodic amnesia (forgets everything from time to time).

Quote:

---

Originally Posted by qny

You opened the FILE for append mode, but then try to read from it ... this is a big no no: don't do that!
Open the file for reading / appending in binary mode like I suggested

Code:

---

    if ( (inSalesPtr = fopen("sales.txt", "a+b") ) == NULL)

---

Note:
the binary mode may be troublesome (or its absence may be troublesome).

Without binary mode, when a file contains "one\r\ntwo\r\n" (10 characters) it is converted to "one\ntwo\n" (8 characters). Using fseek is not guaranteed to go to the expected place.
With binary mode there is no conversion between what's on disk and what your program sees, so "one\r\ntow\r\n" is effectively read as "one\r\ntwo\r\n" and you have to deal with the '\r's yourself.

My suggestion ,assuming you have to deal with Windows line breaks of "\r\n", is to open the files without the binary flag for normal processing, and open them with the binary flag for precision work within the disk-file itself.

---

Change to a+b still the same result. :eek:

You can't open a file in append mode, and then try to read from the file.

You can't fseek() to the end of the file, and then try to read from the file.

I don't know how to make it any plainer than that.

Code:

---

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


// number of salesman
#define SIZE 100
// salesman_type structure definition
typedef struct{
                int ID; // salesman id
                char id_txt[6]; // salesman id for txt file
                char name[50]; // salesman name
                double hor_total; // total sales amount of a salesman 
        }salesman_type; // end structure salesman_type


salesman_type salesman[SIZE];// synonym for salesman_type


// function prototype
int nextId(int currentId, int isReset);
int sale_menu();
int report_menu();
void AddSalesMan(int initialId);


// function to generate id
// currentId and isReset are parameters
int nextId(int currentId, int isReset)
{
        // initializes elements to 0 for the first time function is called
        static int lastId = 0;
        // if isReset is 0, assign currentId to lastId;
        if (isReset == 0)
        {
                lastId = currentId;
        }
        //if isReset is not 0, return and add 1 to lastId
        if (isReset != 0)
                return ++lastId;
}
// sales processing system menu function
int sale_menu()
{
        int menu;
        printf("Sales Processing System\n");
        printf("-----------------------\n\n");
        printf("1. Add Salesman Records\n");
        printf("2. Reports Generation\n");
        printf("3. Modify Salesman Records\n");
        printf("4. Delete Salesman Records\n\n");
        printf("0. Exit\n");
        printf("Your choice: ");
        scanf("%d", &menu);
        return menu;
        printf("\n");
}
// reports generation menu function
int report_menu()
{
        int report;
        printf("Reports Generation\n");
        printf("------------------\n\n");
        printf("1. View Quarterly Sales Report\n");
        printf("2. View Individual Salesman Commission\n\n");
        printf("0. Return to Main Menu\n");
        printf("Your choice: ");
        scanf("%d", &report);
        return report;
}
// function to add salesman
void AddSalesMan(int initialId)
{
        // nextid.txt file pointer
        FILE *writeIdPtr;
        // sales.txt file pointer
        FILE *inSalesPtr;
        char ch;
        int a, b; // counter
        int loop = 1; // confirmation
        int creId = 1; // pass value to nextId function to generate ID
        int newId; // receive new generated ID
        double sale[SIZE][4]; // quarterly sales amount


        // fopen opens file; exit program if unable to create file
        if ( (inSalesPtr = fopen("sales.txt","a+b") ) == NULL)
        {
                printf("Cannot open sales.txt file.\n"); // display error message
                system("pause"); // pause program before it exits
                exit(-1); // end program
        } // end if
        else
        {
                // set the file position to the very last character
                fseek(inSalesPtr, -1, SEEK_END);
                ch = fgetc(inSalesPtr);
                if (ch != '\n')
                {
                        fputs("\r\n",inSalesPtr);
                }
                fclose(inSalesPtr);
        }
        // fopen opens file; exit program if unable to create file
        if ( (writeIdPtr = fopen("nextid.txt","w") ) == NULL)
        {
                printf("Cannot open nextid.txt.\n"); // display error message
                system("pause"); // pause program before it exits
                exit(-1); // end program
        } //end if
        // fopen opens file; exit program if unable to create file
        if ( (inSalesPtr = fopen("sales.txt","a") ) == NULL)
        {
                printf("Cannot open sales.txt file.\n"); // display error message
                system("pause"); // pause program before it exits
                exit(-1); // end program
        } // end if
        else
        {
                // write salesname id, quarterly sales amount into file with fprintf       
                for(a=initialId - 1; a<SIZE; a++)
                {
                        // while loop is 1
                        while (loop == 1)
                        {
                                // assign new generated id to newId
                                newId = nextId(initialId, creId);
                                // write newId into file with fprintf
                                fprintf(inSalesPtr,"S%04d|",newId);
                                //printf("Name: ");
                                //scanf(" %[^\n]", salesman[a].name);
                                for (b=0; b<4; b++)
                                {
                                        // prompt and read quarterly sales amount
                                        printf("Quarter %d: ",b+1);
                                        scanf(" %lf", &sale[a][b]);
                                        // write sales[a][b] into file with fprintf
                                        if(b<3)
                                                fprintf(inSalesPtr,"%.2f|",sale[a][b]);
                                        // end if
                                        else
                                                fprintf(inSalesPtr,"%.2f\n",sale[a][b]);
                                        // end else
                                } // end for       
                                printf("\n");
                                printf("Continue?(Yes = 1): "); // prompt user to continue or not
                                scanf("%d",&loop);
                        } // end while
                } // end for
                // write newId into file with fprintf
                fprintf(writeIdPtr,"%d",newId);
                fclose(writeIdPtr); // flose close the file
                fclose(inSalesPtr); // flose close the file
        } // end else
} // end function AddSalesman


// function main begins program execution
void main()
{
        // nextid.txt file pointer
        FILE *readIdPtr;
        // variable declaration
        int a, b, c = 0, last; // counter
        int getMenu = 0, getReport = 0; // menu selector
        double ver_total = 0, max = 0;
        int id = 0, lastId, resetId = 0;


        // fopen opens the file; exits program if file cannot be opened
        if ( (readIdPtr = fopen("nextid.txt","r") ) == NULL)
        {
                printf("Cannot open nextid.txt file\n");
                system("pause");
                exit(-1);
        } // end if
        else
        {
                // read lastId from file
                fscanf(readIdPtr,"%d",&lastId);
                // Generate new id from previous salesman ID if the salesman is one or more
                // lastId and restId are arguments
                nextId(lastId, resetId);
        } // end else
        // fclose close the file
        fclose(readIdPtr);
        // call and assign sale_menu function to getMenu
        getMenu = sale_menu();
        printf("\n");
        // Execute command based on user input
        switch(getMenu)
        {
                // call AddSalesMan function
                case 1:
                        AddSalesMan(lastId);
                        break;
                // call and assign report_menu to getReport
                case 2:
                        break;
        } // end switch
        system("pause"); // pause the program before it exits       
} // end main

---

Before
Attachment 12154

After
Attachment 12155

Quote:

---

Originally Posted by ulti-killer

[CODE]
Before
Attachment 12154

After
Attachment 12155

---

Is this the expected outcome?

No. My goal is:
Attachment 12156

No matter how the user put line indicator in last line text or any blank line, the new input record can stick with the old record.

My code works for me:

Code:

---

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

int eofnormalize(const char *fname) {
  FILE *h;
  int ch;

  if ((h = fopen(fname, "a+b")) == NULL) return 1;
  if (fseek(h, -1, SEEK_END)) return 2;
  ch = fgetc(h);
  if (ch == EOF) return 3;
  if (ch != '\n') {
    fputs("\r\n", h);
  }
  if (fclose(h)) return 4;
  return 0;
}

int main(void) {
  FILE *h;

  if ((h = fopen("151926.dat", "wb")) == NULL) exit(1);
  fprintf(h, "1 no line break"); /* not a line */
  if (fclose(h)) exit(2);

  if (eofnormalize("151926.dat")) exit(3);

  if ((h = fopen("151926.dat", "a")) == NULL) exit(4);
  fprintf(h, "2 ok\n");
  fclose(h);

  if ((h = fopen("151926.dat", "a")) == NULL) exit(5);
  fprintf(h, "3 windows line break\r\n");
  if (fclose(h)) exit(6);

  if (eofnormalize("151926.dat")) exit(7);

  if ((h = fopen("151926.dat", "a")) == NULL) exit(8);
  fprintf(h, "4 ok\n");
  fclose(h);

  return 0;
}

---

Code:

---

./a.out && echo $? && hd 151926.dat
0
00000000  31 20 6e 6f 20 6c 69 6e  65 20 62 72 65 61 6b 0d  |1 no line break.|
00000010  0a 32 20 6f 6b 0a 33 20  77 69 6e 64 6f 77 73 20  |.2 ok.3 windows |
00000020  6c 69 6e 65 20 62 72 65  61 6b 0d 0a 34 20 6f 6b  |line break..4 ok|
00000030  0a                                                |.|
00000031

---

If I remove the eofnormalize() calls

Code:

---

./a.out && echo $? && hd 151926.dat
0
00000000  31 20 6e 6f 20 6c 69 6e  65 20 62 72 65 61 6b 32  |1 no line break2|
00000010  20 6f 6b 0a 33 20 77 69  6e 64 6f 77 73 20 6c 69  | ok.3 windows li|
00000020  6e 65 20 62 72 65 61 6b  0d 0a 34 20 6f 6b 0a    |ne break..4 ok.|
0000002f

---

In eofnormalize(), a call to a file positioning function is needed between input and output.
I no longer can edit my post, but I'd change the function to:

Code:

---

#include <stdio.h>

int eofnormalize(const char *fname) {
  FILE *h;
  int ch;
 
  if ((h = fopen(fname, "a+b")) == NULL) return 1;
  if (fseek(h, -1, SEEK_END)) return 2;
  ch = fgetc(h);
  if (ch == EOF) return 3;
  if (ch != '\n') {
    fseek(h, 0, SEEK_CUR);
    fputs("\r\n", h);
  }
  if (fclose(h)) return 4;
  return 0;
}

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