Last question for the night. I try not to post more than once per struggle haha...
This one's a bit simpler.
I have a txt file with a series of arranged numbers in the first 8 lines. Every line after is a certain phrase like "BUY ITEM" or "AWARD ITEM" followed by an integer (there are several phrases but I'm only concerned with one). Basically I'm trying to have a for or while loop where I can detect the phrase in the document, set the pointer to the end of the phrase and then fscanf the integer to the right of the phrase. The only trouble I'm having is getting the pointer to the end of the specific phrase and then reading the number. As well as the fact that the phrase is repeated on different lines and I don't want the values to be taken all at once.
I'm sure I can do a simple
while (!feof(//function for reading phrase)) {
fscanf("%d", &value);
//rest of function
And that would be that. But I've tried fseek and fget and nothing has really been able to help get the pointer to the location I need it to without having a preset location of where to go. The input file will be different each time so I can't just tell it to go 1024 spaces down or something like that. Just not sure how you would even go about this...
Also below is an example of an input file.
75 75 908
10 10
18 23.10 10.09
70 5 15
8 100 20 28.99
30 40 50 60
4 6 8 8 5 5 5 6 7 10
10
BUY ITEM 8
BUY ITEM 10
AWARD ITEM 7
BUY ITEM 1
BUY ITEM 3
AWARD ITEM 9
BUY ITEM 7
RETURN ITEM 8
Much appreciation for anyone's help.
Here's an easy way to do it, using the fact that on the lines in question, if your file follows the same format then the numbers will always appear in the same character of the line. This is a little bit fragile, and it'd be better to make your program more robust, to cope with arbitrary amounts of whitespace, for instance, but I'll leave that as an exercise to you:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_LEN 100
#define BUY_LEN 9
#define AWARD_LEN 11
int main(void) {
FILE * infile = fopen("file.dat", "r");
if ( !infile ) {
perror("couldn't open file");
return EXIT_FAILURE;
}
char buffer[MAX_LEN];
char * endptr;
while ( fgets(buffer, MAX_LEN, infile) ) {
if ( !strncmp(buffer, "BUY ITEM ", BUY_LEN ) ) {
char * num_start = buffer + BUY_LEN;
long item = strtol(num_start, &endptr, 0);
if ( endptr == num_start ) {
fprintf(stderr, "Badly formed input line: %s\n", buffer);
return EXIT_FAILURE;
}
printf("Bought item %ld\n", item);
}
else if ( !strncmp(buffer, "AWARD ITEM ", AWARD_LEN) ) {
char * num_start = buffer + AWARD_LEN;
long item = strtol(num_start, &endptr, 0);
if ( endptr == num_start ) {
fprintf(stderr, "Badly formed input line: %s\n", buffer);
return EXIT_FAILURE;
}
printf("Awarded item %ld\n", item);
}
}
fclose(infile);
return 0;
}
Running this with the sample data file in your question, you get:
paul#local:~/src/sandbox$ ./extr
Bought item 8
Bought item 10
Awarded item 7
Bought item 1
Bought item 3
Awarded item 9
Bought item 7
paul#local:~/src/sandbox$
Incidentally, based on one of the suggestions in your question, you might want to check out the answers to the question "while( !feof( file ) )" is always wrong.
Related
I have to read text in from a file, then prompt for a value and search the file for this number. Once the file is read all the way through, I have to print the initial position and the number of times it appears. Obviously I do not just want the answer, but rather where my program went wrong because I am blind to it as of now.
My source code looks like this:
int count, number, value;
printf("What number are you looking for? ");
scanf("%d",&value);
FILE *fp = fopen("data.in","r");
count = 0;
while (!feof(fp)) {
fscanf(fp,"%d",&number);
if (number == value) {
++count;
}
}
fclose(fp);
printf("The number %d appears first at position %d in the file",value,number);
printf("The number %d appears %d time(s)",value,count);
return 0;
}
The data file I am reading from is:
3 8 33 75 25 10 41 8
10
55 10 1 0 10
10 18
However, when I run the program it returns:
What number are you looking for? 10
The number 10 appears first at position 18 in the file
The number 10 appears 5 time(s)
What number are you looking for? -5
The number -5 appears first at position 18 in the file
The number -5 appears 0 time(s)
Any ideas? Again, I am not looking for the straight answer, rather a way for me to look for these issues both now and in the future.
After coming out from while loop number is always the last number i.e. 18
irrespective of number you are looking for.
The line fscanf(fp,"%d",&number); reads the number of each line and when loop terminates the number is assigned as 18.
Also read : “while( !feof( file ) )” is always wrong ?
Do something like following:
int pos = -1, curr_lno = 0 ; // Keep track of position
while (fscanf(fp,"%d",&number) == 1)
{
++curr_lno ;
if (number == value)
{
pos = ( pos == -1 ) ? curr_lno : pos ;
++count;
}
}
fclose(fp);
if ( count > 0 )
{
printf("The number %d appears first at position %d in the file",value, pos );
}
I want to ask something that I write in C.
I use the fopen() command to open and read a text file that contains only two lines. in
first line is an integer N number, and in the second line is the N integer numbers that the first line says.
Eg.
-------------- nubmers.txt --------------
8 <-- we want 8 numbers for the 2nd line
16 8 96 46 8 213 5 16 <-- and we have 8 numbers! :)
but I want to take restrictions when the file openend.
the number N should be between 1 ≤ Ν ≤ 1.000.000. If not then show an error message. If the file is ok then the programm continue to run with another code.
Here is what I done until now:
int num;
....
fscanf(fp,"%d",&num); // here goes the fscanf() command
if(num<1 || num>1000000) // set restrictions to integer
{
printf("The number must be 1<= N <= 1.000.000",strerror(errno)); // error with the integer number
getchar(); // wait the user press a key
return 0; // returning an int of 0, exit the program
}
else // if everything works.....
{
printf("work until now"); // Everything works until now! :)
getchar(); // wait the user press a key
return 0; // returning an int of 0, exit the program
}
But the problem is that the restriction checks only for the first line number , it's correct though, but don't read the numbers in the second line.
What I mean is that :
Lets say that I have the number 10 in the first line.
The code will analyze the number, will check for restrictions and will proceed to the 'else' part
else // if everything works.....
{
printf("work until now"); // Everything works until now! :)
getchar(); // wait the user press a key
return 0; // returning an int of 0, exit the program
}
..and it will said that everything is working.
But what if I have 20 numbers in the second line? -when I need only 10
Eg.
-------------- nubmers.txt --------------
10
16 8 96 46 8 213 5 16 8 9 21 5 69 64 58 10 1 7 3 6
So I hoped be as cleared as I could. My question is that I need a code in the program, besides the 1st restriction, that have also another one restriction under the first that will read the second line of the txt file with the numbers and check if there are as many numbers as the first line says!
How do I do that?
If you guys want any other declarations feel free to ask!
Hope I was clear with my problem :)
This will check the number of integers and report too many or not enough. The integers are not saved except for each one being read into the value. Do you want to store each integer?
fscanf(fp,"%d",&num); // here goes the fscanf() command
if(num<1 || num>1000000) // set restrictions to integer
{
printf("The number must be 1<= N <= 1.000.000",strerror(errno)); // error with the integer number
getchar(); // wait the user press a key
return 0; // returning an int of 0, exit the program
}
else // if everything works.....
{
int i = 0;
int value = 0;
while ( fscanf ( fp, "%d", &value) == 1) { // read one integer
i++; // this loop will continue until EOF or non-integer input
}
if ( i > num) {
printf ( "too many integers\n");
}
if ( i < num) {
printf ( "not enough integers\n");
}
getchar(); // wait the user press a key
return 0; // returning an int of 0, exit the program
}
use a loop that takes the first num and checks is is the number of integers in next line:
int z = num;
while(z--){
if (getchar() == EOF)
printf("err")
}
Do it like this:
fscanf(fp,"%d",&num);
// next lines of code (restrictions). Then place the below code before getchar in the else
int temp[num+1];// space to store num integers to temp and 1 space to check for extra number
for(i=0;i<num;i++)
{
if(fscanf(fp,"%d",&temp[i]) != 1)// fscanf will automatically read 2nd line and store them in temp array
//error ! Less numbers in file !
}
if(fscanf(fp,"%d",&temp[num]==1) //if still numbers can be scanned
//Extra numbers found in line 2
Hello I have file with text:
14
5 4
45 854
14
4
47 5
I need to write a text to a specific line. For example to the line number 4 (Doesn't matter whether I will append the text or rewrite the whole line):
14
5 4
45 854
14 new_text
4
47 5
I have found function fseek(). But in the documentation is written
fseek(file pointer,offset, position);
"Offset specifies the number of positions (bytes) to be moved from the location specified bt the position."
But I do not know the number of bites. I only know the number of lines. How to do that? Thank you
You can't do that, (text) files are not line-addressable.
Also, you can't insert data in the middle of a file.
The best way is to "spool" to a new file, i.e. read the input line by line, and write that to a new file which is the output. You can then easily keep track of which line you're on, and do whatever you want.
I will assume that you are going to be doing this many times for a single file, as such you would be better indexing the position of each newline char, for example you could use a function like this:
long *LinePosFind(int FileDes)
{
long * LinePosArr = malloc(500 * sizeof(long));
char TmpChar;
long LinesRead = 0;
long CharsRead = 0;
while(1 == read(FileDes, &TmpChar, 1))
{
if (!(LinesRead % 500)
{
LinePosArr = realloc(LinePosArr, (LinesRead + 500) * sizeof(long));
}
if (TmpChar == '\n')
{
LinePosArr[LinesRead++] = CharsRead;
}
CharsRead++;
}
return LinePosArr;
}
Then you can save the index of all the newlines for repeated use.
After this you can use it like so:
long *LineIndex = LinePosFind(FileDes);
long FourthLine = LineIndex[3];
Note I have not checked this code, just written from my head so it may need fixes, also, you should add some error checking for the malloc and read and realloc if you are using the code in production.
First time I have asked a question here. First here's the code:
void displayCompanyInfo(STAFF e[], int *s)
{
FILE *payRoll;
int i = 0;
int rosterNumber [100];
int count = 1;
if ((payRoll = fopen("payRoll.txt", "r")) == NULL)
{
perror ("error");
exit (0);
}
cls;
while (fgets(e[i].name, sizeof(e[i].name), payRoll) != NULL)
{
printf ("Record %i: ", count++);
printf("%s\n", e[i].name);
}
fclose(payRoll);
printf("\n\n");
pause;
cls;
} // end of display
Basically this code works. However when the text file displays it reads like this:
Record 1: Name: blah
Record 2: Age: 23
Record 3: Hourly Rate: 34
Instead I want it to read it as follows:
Record 1: Name: Blah
Age: 23
Hourly Rate: 34
Record 2: Name: Blah2
Age: 24
Hourly Rate: 35
And so on...
Any idea on how I can get this to work. I didn't post whole program because I didn't want to over do my thread. But if you need it let me know.
To this case you have to work with binary file handling.With text file it is not possible.
You have to read,write chunk of data in terms of bytes and handle it accordingly to retrieve you structure.
Say
struct e{
char name[20],
int age,
int hourly_rate
};
This structure will require
20(name) + 4(age) + 4(hourly_rate) bytes.Then you should write 28 bytes at a time in binary file and retrieve 28 bytes accordingly,which is not possible in case of text file.Because text file considers every thing as character,say age=23 it considers age field as 2 bytes and if age=3,it consider it as 1 byte.But binary file considers both thing as 4 bytes which is actual size of integer.
So the solution to your problem is binary file handling.
The problem is that the loop considers each line as a record. Instead, a record should be 3 lines. So read 3 things in the loop - add the 2 missing right before the printf.
A text file holds information about a softball team. Each line has data arranged as follows:
4 Jessie Joybat 5 2 1 1
The first item is the player's number, conveniently in the range 0–18. The second item is the player's first name, and the third is the player's last name. Each name is a single word. The next item is the player's official times at bat, followed by the number of hits, walks, and runs batted in (RBIs). The file may contain data for more than one game, so the same player may have more than one line of data, and there may be data for other players between those lines. Write a program that stores the data into an array of structures. The structure should have members to represent the first and last names, the at bats, hits, walks, and RBIs (runs batted in), and the batting average (to be calculated later). You can use the player number as an array index. The program should read to end-of-file, and it should keep cumulative totals for each player.
The world of baseball statistics is an involved one. For example, a walk or reaching base on an error doesn't count as an at-bat but could possibly produce an RBI. But all this program has to do is read and process the data file, as described next, without worrying about how realistic the data is.
The simplest way for the program to proceed is to initialize the structure contents to zeros, read the file data into temporary variables, and then add them to the contents of the corresponding structure. After the program has finished reading the file, it should then calculate the batting average for each player and store it in the corresponding structure member. The batting average is calculated by dividing the cumulative number of hits for a player by the cumulative number of at-bats; it should be a floating-point calculation. The program should then display the cumulative data for each player along with a line showing the combined statistics for the entire team.
team.txt (text file I'm working with):
4 Jessie Joybat 5 2 1 1
4 Jessie Joybat 7 3 5 3
7 Jack Donner 6 3 1 2
11 Martin Garder 4 3 2 1
15 Jaime Curtis 7 4 1 2
2 Curtis Michel 3 2 2 3
9 Gillan Morthim 9 6 6 7
12 Brett Tyler 8 7 4 3
8 Hans Gunner 7 7 2 3
14 Jessie James 11 2 3 4
12 Brett Tyler 4 3 1 3
Since I'm a beginner in C, either I misinterpreted the task from what was asked originally or it's unfairly complex (I believe the former is the case). I'm so lost that I can't think of the way how could I fill in by the criteria of index (player number) every piece of data, keep track of whether he has more than one game, calculate and fetch bat average and then print.
What I have so far is:
#define LGT 30
struct profile {
int pl_num;
char name[LGT];
char lname[LGT];
int atbat[LGT/3];
int hits[LGT/3];
int walks[LGT/3];
int runs[LGT/3];
float batavg;
};
//It's wrong obviously but it's a starting point
int main(void)
{
FILE *flx;
int i,jc,flow=0;
struct profile stat[LGT]={{0}};
if((flx=fopen("team.txt","r"))==NULL) {
fprintf(stderr,"Can't read file team!\n");
exit(1);
}
for( jc = 0; jc < 11; jc++) {
fscanf(flx,"%d",&i);
stat[i].pl_num=i;
fscanf(flx,"%s",&stat[i].name);
fscanf(flx,"%s",&stat[i].lname);
fscanf(flx,"%d",&stat[i].atbat[flow]);
fscanf(flx,"%d",&stat[i].hits[flow]);
fscanf(flx,"%d",&stat[i].walks[flow]);
fscanf(flx,"%d",&stat[i].runs[flow]);
flow++;
}
}
Advice 1: don't declare arrays like atbat[LGT/3].
Advice 2: Instead of multiple fscanf you could read the whole line in a shot.
Advice 3: Since the number of players is limited and the player number has a good range (0-18), using that player number as an index into the struct array is a good idea.
Advice 4: Since you need cumulative data for each player (no need to store his history points), then you don't need arrays of integers, just an integer to represent the total.
So:
#include <stdio.h>
#define PLAYERS_NO 19
typedef struct
{
char name[20+1];
char lastName[25+1];
int atbat;
int hits;
int walks;
int runs;
float batavg;
} Profile;
int main(int argc, char** argv)
{
Profile stats[PLAYERS_NO];
int i;
FILE* dataFile;
int playerNo;
Profile tmpProfile;
int games = 0;
for(i=0; i<PLAYERS_NO; ++i)
{
stats[i].name[0] = '\0';
stats[i].lastName[0] = '\0';
stats[i].atbat = 0;
stats[i].hits = 0;
stats[i].walks = 0;
stats[i].runs = 0;
}
dataFile = fopen("team.txt", "r");
if ( dataFile == NULL )
{
fprintf(stderr, "Can't read file team!\n");
exit(1);
}
for(i=0; i<PLAYERS_NO && !feof(dataFile); ++i, ++games)
{
fscanf(dataFile, "%d", &playerNo);
if ( playerNo <0 || playerNo > PLAYERS_NO )
{
fprintf(stderr, "Player number out of range\n");
continue;
}
fscanf(dataFile, "%s %s %d %d %d %d",
&tmpProfile.name,
&tmpProfile.lastName,
&tmpProfile.atbat,
&tmpProfile.hits,
&tmpProfile.walks,
&tmpProfile.runs);
printf("READ: %d %s %s %d %d %d %d\n",
playerNo,
tmpProfile.name,
tmpProfile.lastName,
tmpProfile.atbat,
tmpProfile.hits,
tmpProfile.walks,
tmpProfile.runs);
strcpy(stats[playerNo].name, tmpProfile.name);
strcpy(stats[playerNo].lastName, tmpProfile.lastName);
stats[playerNo].atbat += tmpProfile.atbat;
stats[playerNo].hits += tmpProfile.hits;
stats[playerNo].walks += tmpProfile.walks;
stats[playerNo].runs += tmpProfile.runs;
}
/* exercise: compute the average */
fclose(dataFile);
for(i=0; i<PLAYERS_NO; ++i)
{
if ( stats[i].name[0] == '\0' )
continue;
printf("%d %s %s %d %d %d %d\n",
i,
stats[i].name,
stats[i].lastName,
stats[i].atbat,
stats[i].hits,
stats[i].walks,
stats[i].runs);
}
return 0;
}
The first rule of programming: Divide and conquer.
So you need to identify individual operations. One such operation is "load one row of input", another is "look up a player". If you have some of those operations (more will come up as you go), you can start building your program:
while( more_input ) {
row = load_one_row()
player = find_player( row.name )
if( !player ) {
player = create_player( row.name )
add_player( player )
}
... do something with row and player ...
}
when you have that, you can start to write all the functions.
An important point here is to write test cases. Start with a simple input and test the code to read a row. Do you get the correct results?
If so, test the code to find/create players.
The test cases make sure that you can forget about code that already works.
Use a framework like Check for this.
If I were doing this, I'd start with a structure that only held one "set" of data, then create an array of those structs:
struct profile {
char name[NAMELEN];
char lname[NAMELEN];
int atbat;
int hits;
int walks;
int runs;
float batavg;
};
Since you're using the player's number as the index into an array, you don't need to store it into the structure too.
I think that will simplify the problem a little bit. You don't need to store multiple data items for a single player -- when you get a duplicate, you just ignore some of the new data (like the names, which should be identical) and sum up the others (e.g., at-bats, hits).