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11-14-2005, 02:17 PM
| #1 |
| Registered User Join Date: Oct 2005
Posts: 63
| Inventory records Code:
#include <stdio.h>
/* hardwareData structure definition */
struct hardwareData {
int recordNum;
char toolname[20];
int quantity;
double cost;
}; /* end structure hardwareData */
int main()
{
FILE *hfPtr; /* hardware.dat file pointer */
/* create hardwareData with default information */
struct hardwareData hardware = { 0, "", 0,0.0 };
/* fopen opens file; exits if file cannot be opened */
if ((hfPtr = fopen( "hardware.dat", "rb+" )) == NULL ) {
printf( "File could not be opened.\n" );
} /* end if */
else{
/* require user to specift record number */
printf( "Enter record number"
"( 1 to 100, 0 to end input)\n" );
scanf( "%d", &hardware.recordNum );
/* user enters information, which is copied into file */
while ( hardware.recordNum != 0 ) {
/* user enters tool name, quantity and cost */
printf ( "Enter tool name, quantity, cost\n? " );
/* set record tool name, quantity and cost */
fscanf( stdin, "%s%d%f", hardware.toolname, hardware.quantity, &hardware.cost );
/* seek position in file to user-specified record */
fseek( hfPtr, ( hardware.recordNum - 1 ) *
sizeof( struct hardwareData ), SEEK_SET );
/* write user-specified information in file */
fwrite( &hardware, sizeof( struct hardwareData ), 1, hfPtr );
/* enable user to input another record number */
printf( " Enter record number\n?" );
scanf( "%d", &hardware.recordNum );
} /* end while */
fclose( hfPtr ); /* fclose closes file */
} /* end else */
return 0; /* indicates successful termination */
} /* end main */
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| jsbeckton is offline |  |
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11-14-2005, 02:19 PM
| #2 |
| Registered User Join Date: Oct 2005
Posts: 63
| nevermind I found the eror, does this satisfy the requirements as listed above? |
| jsbeckton is offline | |
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11-14-2005, 02:53 PM
| #3 |
| Registered User Join Date: Mar 2005
Posts: 140
| No, it doesn't satisfy the requirements. Seems like a silly question. Do you really need someone to answer that for you? can you list all the tools? can you delete a tool? can you update a tool? My guess is you need a menu of some sort, where you give choices to, Add, Update, Delete, or Show All tools. |
| spydoor is offline | |
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11-15-2005, 09:34 AM
| #4 |
| Registered User Join Date: Oct 2005
Posts: 63
| cant I just re-enter that record as balnk and delete or update the tool? |
| jsbeckton is offline | |
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11-15-2005, 12:48 PM
| #5 |
| Registered User Join Date: Mar 2005 Location: Mountaintop, Pa
Posts: 1,054
| I'm not sure I'd want to use the following code: Code: /* seek position in file to user-specified record */
fseek( hfPtr, ( hardware.recordNum - 1 ) *
sizeof( struct hardwareData ), SEEK_SET );
/* write user-specified information in file */
fwrite( &hardware, sizeof( struct hardwareData ), 1, hfPtr );
You may want to consider reading the records into a linked list or struct array, processsing the records and then writing the records back out to the file from the LL or struct array. |
| BobS0327 is offline | |
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11-15-2005, 03:47 PM
| #6 |
| Registered User Join Date: Oct 2005
Posts: 63
| I am now moving in a different direction with this, Ive created a menu, and finished the text file but have come up with an error and a few warnings saying: error C2065: 'hfPtr' : undeclared identifier warning C4047 '=' : 'int ' differs in levels of indirection from 'struct _iobuf *' warning C4047: '==' : 'int ' differs in levels of indirection from 'void *' warning C4133: 'function' : incompatible types - from 'char [29]' to 'struct _iobuf *' warning C4133: 'function' : incompatible types - from 'char [22]' to 'struct _iobuf *' does anyone see what I've done wrong and anycoments on this code would be appreciated, thanks Code: #include <stdio.h>
/* hardwareData structure definition */
struct hardwareData {
int recordNum;
char toolname[20];
int quantity;
double cost;
}; /* end structure hardwareData */
/* prototypes */
int enterChoice( void );
void textFile( FILE *readPtr );
void updateRecord( FILE *fPtr );
void newRecord( FILE *fPtr );
void deleteRecord( FILE *fPtr );
int main()
{
FILE *hfPtr; /* hardware.dat file pointer */
int choice; /* user choice */
/* fopen opens file; exits if file cannot be opened */
if ((hfPtr = fopen( "hardware.dat", "rb+" )) == NULL ) {
printf( "File could not be opened.\n" );
} /* end if */
else {
/* enable user to specify action */
while (( choice = enterChoice()) != 5 ) {
switch ( choice ) {
/* create text file from record */
case 1:
textFile( hfPtr );
break;
/* update record */
case 2:
updateRecord( hfPtr );
break;
/* create record */
case 3:
newRecord ( hfPtr );
break;
/* delete existing record */
case 4:
deleteRecord ( hfPtr );
break;
/* display message if user does not enter valid choice */
default:
printf( "Incorrect choice\n" );
break;
} /* end switch */
} /* end while */
fclose( hfPtr ); /* fclose closes the file */
} /* end else */
return 0; /* indicate successful termination */
} /* end main */
/* create formated text for printing */
void textFile( FILE *readPtr )
{
FILE *writePtr; /* hardware.txt file pointer */
/* create hardwareData with default information */
struct hardwareData hardware = { 0, "", 0,0.0 };
/* fopen opens file; exits if file cannot be opened */
if ((hfPtr = fopen( "hardware.dat", "rb+" )) == NULL ) {
printf( "File could not be opened.\n" );
} /* end if */
else{
rewind( readPtr ); /* sets pointer to begining of file */
fprintf( "writePtr, %-6s%-10s%-8s%-8s\n",
"Record#", "Tool name", "Quantity", "Cost" );
/* copy all records from random-access file to text file */
while ( !feof( readPtr ) ) {
fread( &hardware, sizeof( struct hardwareData ),1, readPtr );
/* write single record to text file */
if ( hardware.recordNum != 0 ) {
fprintf( "%-6d%-16s%-11d%10.2f\n",
hardware.toolname, hardware.quantity, hardware.cost );
} /* end if */
} /* end while */
fclose( writePtr ); /* fclose closes file */
} /* end else */
} /* end function textrFile */
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| jsbeckton is offline | |
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11-15-2005, 04:04 PM
| #7 |
| Just Lurking  Join Date: Oct 2002
Posts: 4,990
| Well, undeclared identifier is pretty easy: Code: /* create formated text for printing */
void textFile( FILE *readPtr )
{
FILE *writePtr; /* hardware.txt file pointer */
/* create hardwareData with default information */
struct hardwareData hardware = { 0, "", 0,0.0 };
/* fopen opens file; exits if file cannot be opened */
if ((hfPtr = fopen( "hardware.dat", "rb+" )) == NULL ) {
printf( "File could not be opened.\n" );
} /* end if */
else{
rewind( readPtr ); /* sets pointer to begining of file */
fprintf( "writePtr, %-6s%-10s%-8s%-8s\n",
"Record#", "Tool name", "Quantity", "Cost" );
/* copy all records from random-access file to text file */
while ( !feof( readPtr ) ) {
fread( &hardware, sizeof( struct hardwareData ),1, readPtr );
/* write single record to text file */
if ( hardware.recordNum != 0 ) {
fprintf( "%-6d%-16s%-11d%10.2f\n",
hardware.toolname, hardware.quantity, hardware.cost );
} /* end if */
} /* end while */
fclose( writePtr ); /* fclose closes file */
} /* end else */
} /* end function textrFile */
__________________ 7. It is easier to write an incorrect program than understand a correct one. 40. There are two ways to write error-free programs; only the third one works.* |
| Dave_Sinkula is offline | |
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11-15-2005, 06:18 PM
| #8 |
| Registered User Join Date: Oct 2005
Posts: 63
| I dont understand the problem with the undeclared identifier, are they not all declared in the prototypes? |
| jsbeckton is offline | |
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11-15-2005, 08:30 PM
| #9 |
| Just Lurking Join Date: Oct 2002
Posts: 4,990
| Where is hfPtr declared in a prototype? Or more to the point, since the name of a parameter in the prototype doesn't matter, where is it declared in the function? (The compiler is asking you the same question.) [edit]While we're at it: FAQ > Explanations of... > Why it's bad to use feof() to control a loop
__________________ 7. It is easier to write an incorrect program than understand a correct one. 40. There are two ways to write error-free programs; only the third one works.* Last edited by Dave_Sinkula; 11-15-2005 at 09:14 PM. |
| Dave_Sinkula is offline | |
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11-17-2005, 08:32 AM
| #10 |
| Registered User Join Date: Oct 2005
Posts: 63
| I fixed the hfPtr, it was the others that I thought were declared in the prototype. Its now giving me an error that says writePr is being used without having been initialized but I thought that this had initialized it. Code: /* create formated text for printing */
void textFile( FILE *readPtr )
{
FILE *writePtr; /* hardware.txt file pointer */
/* create hardwareData with default information */
struct hardwareData hardware = { 0, "", 0,0.0 };
/* fopen opens file; exits if file cannot be opened */
if ((hfPtr = fopen( "hardware.dat", "rb+" )) == NULL ) {
printf( "File could not be opened.\n" );
} /* end if */
else{
rewind( readPtr ); /* sets pointer to begining of file */
fprintf( writePtr, "%-6s%-10s%-8s%-8s\n",
"Record#", "Tool name", "Quantity", "Cost" );
Last edited by jsbeckton; 11-17-2005 at 08:37 AM. |
| jsbeckton is offline | |
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11-17-2005, 10:08 AM
| #11 |
| Registered User Join Date: Oct 2005
Posts: 63
| Still having that error with the rest of the code completed, anyone have and ideas? It compiles as is but when I try to enter information it must have a continous loop or something? Code: /* hardwareware.dat */
#include <stdio.h>
/* hardwareData structure definition */
struct hardwareData {
int recordNum;
char toolname[20];
int quantity;
double cost;
}; /* end structure hardwareData */
/* prototypes */
int enterChoice( void );
void textFile( FILE *readPtr );
void updateRecord( FILE *fPtr );
void newRecord( FILE *fPtr );
void deleteRecord( FILE *fPtr );
FILE *hfPtr; /* hardware.dat file pointer */
int main()
{
FILE *hfPtr; /* hardware.dat file pointer */
int choice; /* user choice */
/* fopen opens file; exits if file cannot be opened */
if ((hfPtr = fopen( "hardware.dat", "rb+" )) == NULL ) {
printf( "File could not be opened.\n" );
} /* end if */
else {
/* enable user to specify action */
while (( choice = enterChoice()) != 5 ) {
switch ( choice ) {
/* create text file from record */
case 1:
textFile( hfPtr );
break;
/* update record */
case 2:
updateRecord( hfPtr );
break;
/* create record */
case 3:
newRecord ( hfPtr );
break;
/* delete existing record */
case 4:
deleteRecord ( hfPtr );
break;
/* display message if user does not enter valid choice */
default:
printf( "Incorrect choice\n" );
break;
} /* end switch */
} /* end while */
fclose( hfPtr ); /* fclose closes the file */
} /* end else */
return 0; /* indicate successful termination */
} /* end main */
/* create formated text for printing */
void textFile( FILE *readPtr )
{
FILE *writePtr; /* hardware.txt file pointer */
/* create hardwareData with default information */
struct hardwareData hardware = { 0, "", 0,0.0 };
/* fopen opens file; exits if file cannot be opened */
if ((hfPtr = fopen( "hardware.txt", "rb+" )) == NULL ) {
printf( "File could not be opened.\n" );
} /* end if */
else{
rewind( readPtr ); /* sets pointer to begining of file */
fprintf( writePtr, "%-6s%-10s%-8s%-8s\n",
"Record#", "Tool name", "Quantity", "Cost" );
/* copy all records from random-access file to text file */
while ( !feof( readPtr ) ) {
fread( &hardware, sizeof( struct hardwareData ),1, readPtr );
/* write single record to text file */
if ( hardware.recordNum != 0 ) {
fprintf( "%-6d%-16s%-11d%10.2f\n",
hardware.toolname, hardware.quantity, hardware.cost );
} /* end if */
} /* end while */
fclose( writePtr ); /* fclose closes file */
} /* end else */
} /* end function textrFile */
/* update record */
void updateRecord ( FILE *fPtr )
{
int record; /* record number */
/* create record data with no information */
struct hardwareData hardware = { 0, "", 0,0.0 };
/* obtain number of account to update */
printf( "Enter record to update (0-100): ");
scanf( "%d", &record );
/* move file pointer to correct record */
fseek( fPtr, ( record - 1 ) * sizeof( struct hardwareData ),
SEEK_SET );
/* read record from file */
fread( &record, sizeof( struct hardwareData ), 1, fPtr );
/* display error if record does not exist */
if ( hardware.recordNum == 0) {
printf( "Record #%d has no information.\n", record );
} /* end if */
else { /* update record */
printf( "Enter new tool name, quantity,cost \n?" );
scanf( "%s%d%f", hardware.toolname, hardware.quantity, hardware.cost );
fseek( fPtr, ( record - 1 ) * sizeof( struct hardwareData ),
SEEK_SET );
/* write updated record over old record */
fwrite( &hardware, sizeof( struct hardwareData ), 1, fPtr );
} /* end else */
} /* end function update record */
/* delete an existing record */
void deleteRecord( FILE *fPtr )
{
struct hardwareData hardware; /* stores record read form file */
struct hardwareData blankRecord = { 0, "", 0,0.0 }; /* blank record */
int recordNum;
/* obtain number of record to delete */
printf( "Enter record number to delete (0-100): " );
scanf( "%d", &recordNum );
/* move file pointer to correct file */
fseek( fPtr, ( recordNum - 1 ) * sizeof( struct hardwareData ),
SEEK_SET );
/* read record from file */
fread( &hardware, sizeof( struct hardwareData ), 1, fPtr );
/* display error if record does not exist */
if ( hardware.recordNum==0 ) {
printf ( "Record %d does not exist.\n", recordNum );
} /* end if */
else { /* delete record */
/* move file pointer to correct record */
fseek( fPtr, ( recordNum - 1 ) * sizeof( struct hardwareData ),
SEEK_SET );
/* replace existing record with blank record */
fwrite( &blankRecord,
sizeof( struct hardwareData ), 1, fPtr );
} /* end else */
} /* end function delete record */
/* create and insert record */
void newRecord( FILE *fPtr )
{
/* create recordData with default information */
struct hardwareData hardware = { 0, "", 0,0.0 };
int recordNum;
/* obtain record number to create */
printf( "Enter record number to create (1-100) : " );
scanf( "%d", &recordNum );
/* move file pointer to correct record */
fseek( fPtr, ( recordNum - 1 ) * sizeof( struct hardwareData ),
SEEK_SET );
/* read record */
fread( &hardware, sizeof( struct hardwareData ), 1, fPtr );
/* display error if record already exists */
if ( hardware.recordNum != 0 ) {
printf( "Record already exists" );
} /* end if */
else { /* create record */
/* user enters toolname, quantity and cost */
printf( "Enter tool name, quantity, cost\n" );
scanf( "%s%d%f", &hardware.toolname, &hardware.quantity, &hardware.cost );
/* move file pointer to correct record */
fseek( fPtr, ( recordNum - 1 ) * sizeof( struct hardwareData ),
SEEK_SET );
/* insert record into file */
fwrite( &hardware,
sizeof( struct hardwareData ), 1, fPtr );
} /* end else */
} /* end function newRecord */
/* enable user to input menu choice */
int enterChoice( void )
{
int menuChoice; /* variable to stoer users choice */
/* display available options */
printf( "\nEnter your choice\n"
"1 - store a formatted text file of records called\n"
" \"hardware.txt\"for printing\n"
"2 - update a record\n"
"3 - add a new record\n"
"4 - delete a record\n"
"5 - end program\n? " );
scanf( "%d", & menuChoice ); /* recieve choice from user */
return menuChoice;
} /* end function enterChoice */
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| jsbeckton is offline | |
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11-17-2005, 12:40 PM
| #12 |
| Registered User Join Date: Oct 2005
Posts: 63
| It brings up the menu, lets me enter a choice, since there is currently nothing in the file, I choose 3 "enter new record number" which works fine by bring up the line "enter tool name, quantity, cost" however when i enter the information and hit enter, the program continously reprints the menu over and over until I close it. |
| jsbeckton is offline | |
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11-17-2005, 01:12 PM
| #13 |
| Just Lurking Join Date: Oct 2002
Posts: 4,990
| Your problem is likely that you are using scanf for input. When you enter a number the newline is left in the input buffer. There are better ways to get input, both for numbers and for strings. These are described in the FAQ, as well as clearing the input buffer of such things as a leftover newline.
__________________ 7. It is easier to write an incorrect program than understand a correct one. 40. There are two ways to write error-free programs; only the third one works.* |
| Dave_Sinkula is offline | |
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11-17-2005, 01:29 PM
| #14 |
| Registered User Join Date: Oct 2005
Posts: 63
| Is it not possible to use scanf to get input for this? I'm just asking because thats how they have been doing it in my book. Would it not be easieer to fix this rather than redo all of the input functions? |
| jsbeckton is offline | |
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