Reading from multiple files into a struct - c

Question

I am having trouble with an assignment, it involves reading from files into structures and I'm confused on how to do it here is the function with the parameters I HAVE to use.
// This function will read in size struct players from filename and add these
// the players array. The function will use index to know where to start
// writing the players to in the array.
// Parameters
//
// filename – The name of the input file
// players – a pointer to the array of player structures
// index – The index of the array to start placing players into
// size – The number of players in the input file
// Return - Nothing
void read_from_file(char* filename, Player* players, int index, int size);
This is the function I have to use to read in data from 3 DIFFERENT files that look as such:
Andrew Jackson 129 33 38 30 506
Jeremy Warden 25 24 3 9 493
Jared Welch 130 1 43 27 422
Brandon Splitter 138 38 40 7 587
Joe Gwilliams 150 23 30 25 498
Ali Mohammed 119 43 13 6 598
Dheeraj Johnson 124 79 59 36 506
Bill Clinton 121 65 12 26 449
Jesse James 87 58 8 5 464
John Doe 129 100 0 12 548
I have to read in 3 files that all have 10 players in them for a total of 30 I need to read into the structures. I have not gotten very far I know but I am very confused on what to do and how to approach this, any help would be very much appreciated! Below I have down what I have already done. Please help!! Thanks
//Brady Webb
//lab D
//HW1
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
typedef struct player
{
char Fname[25];
char Lname[25];
int Singles;
int Doubles;
int Triples;
int Homeruns;
int At_Bats;
float Slugging_Percentage;
} Player;
void read_from_file(char* filename, Player* players, int index, int size);
int main(int argc, char* argv[])
{
int size= atoi(*(argv+1));
char* file1 = *(argv+2);
char* file2 = *(argv+3);
char* file3 = *(argv+4);
if (argc<6 || argc>6)
{
printf("Incorrect command line arguments\n");
return 0;
}
return 0;
}
void read_from_file(char*filename, Player* players, int index, int size)
{
FILE *ptr;
int i=0;
if ((ptr=fopen(filename, "r")) == NULL)
{
return 0;
}
while (ptr != EOF)
{
}
}

Answer 1

The simplest approach to read file with regular structure is to use fscanf with complex format string.
fscanf("%s %s %d %d %d %d %d", Player.Fname, Player.Lname,
&Player.Singles, &Player.Doubles,
&Player.Triples, &Player.Homeruns, &Player.At_Bats);
You should make a loop to read till the and of file, and you can add the check of reading the data in the correct format, e.g.:
int check = fscanf("%s %s %d %d %d %d %d", Player.Fname, Player.Lname,
&Player.Singles, &Player.Doubles,
&Player.Triples, &Player.Homeruns, &Player.At_Bats);
if( check != 7 )
{
// stop reading and report on wrong file format
}
UPDATE:
I propose the following code as possible solution:
// This function will read in size struct players from filename and add these
// the players array. The function will use index to know where to start
// writing the players to in the array.
// Parameters
//
// filename – The name of the input file
// players – a pointer to the array of player structures
// index – The index of the array to start placing players into
// size – The number of players in the input file
// Return - number of read players (positive number)
// or error code (negarive number)
int read_from_file(char * filename, Player* players, int index, int size)
{
struct player ptmp;
FILE *fptr;
// open the file
if ((fptr = fopen(filename, "r")) == NULL)
{
fprintf(stderr, "File %s cannot be oppened\n",filename);
return -1; // error code for "File cannot be oppened"
}
// reading from file
int position = index;
int cnt = 0;
while (!ferror(fptr) && cnt < size)
{
int check = fscanf(fptr, "%24s %24s %d %d %d %d %d", ptmp.Fname, ptmp.Lname,
&ptmp.Singles, &ptmp.Doubles, &ptmp.Triples, &ptmp.Homeruns, &ptmp.At_Bats);
if (feof(fptr) && check != 7)
{
break;
}
if (check != 7)
{
fclose(fptr);
fprintf(stderr,"Wrong data format in line %d of file %s\n", cnt+1, filename);
return -2; // error code for "File has wrong data format"
}
// copy data to players
players[index++] = ptmp;
cnt++;
}
// close the file
fclose(fptr);
return cnt;
}
Pay attention at changed type of function read_from_file - I described my idea concerning return value in the comments.
And main in my understanding should be like:
int main(int argc, char* argv[])
{
Player players[30]; // memory is allocated for particular number of data items
// check the command line arguments
if (argc < 3)
{
printf("Please run the program in the format:\n");
printf(" %s 2 firstFile.txt secondFile.txt\n", argv[0]);
printf(" where 2 is number of files given after 2 with data to be read\n");
return 0;
}
int fileNumber = 0;
if (!sscanf(argv[1], "%d", &fileNumber) || fileNumber <= 0)
{
printf("The first command line argument nust be positive number.\n");
printf("Run program without parameters to see details\n");
return 0;
}
if (fileNumber != (argc - 2))
{
printf("Command line arguments are inconsistent\n");
printf("Run program without parameters to see details\n");
return 0;
}
// file processing
int i = 0;
int total = 0;
int max = 30;
for (i = 0; i < fileNumber; i++)
{
printf("Reading from %s...\n", argv[i + 2]);
int res = read_from_file(argv[i + 2], players, total, max);
if (res > 0)
{
total += res;
max -= res;
}
}
// check data
for (i = 0; i < total; i++)
{
printf("%s %s : %d %d %d %d %d\n", players[i].Fname, players[i].Lname, players[i].Singles, players[i].Doubles, players[i].Triples, players[i].Homeruns, players[i].At_Bats);
}
return 0;
}
It is assumed that 30 players can be read any number of files, and not necessarily to 10 of each file.

Answer 2

The loop can be return to read one line at a time and each line can be passed to a helper function like getPlayer
char *line;
char buffer[256]; // assuming that's the longest line size
while ((line = fgets(buffer, sizeof(buffer), ptr)) != NULL) {
Player *pl = getPlayer(line);
//...
}
The above code should replace loop in the code posted as while (ptr != EOF). The getPlayer can be something along the following lines (the player can then be added to list/array etc. and make sure you free up accordingly when you are done)
Player *getPlayer(char *line) {
Player *iPlayer = (Player *)malloc(sizeof(Player));
sscanf(line, "%s %s %d %d %d %d %d %f",
iPlayer->Fname,
iPlayer->Lname,
&iPlayer->Singles,
&iPlayer->Doubles,
&iPlayer->Triples,
&iPlayer->Homeruns,
&iPlayer->At_Bats,
&iPlayer->Slugging_Percentage);
return iPlayer;
}

Answer 3

struct Player PlayerArr[10];
void read_from_file(char*filename, Player* players, int index, int size)
{
FILE *ptr;
int i=0;
char content[50];
memset(content, '\0', 50);
if ((ptr=fopen(filename, "r")) == NULL)
{
return 0;
}
while (ptr != EOF)
{
getline(infile,line);
memset(content,'\0',sizeof(content));
strcpy(content,line.c_str());
ReadNextConfRecord(content);
}
return 0;
}
int ReadNextConfRecord(char *content)
{
char str[50];
const char delimiter[2] = " ";
char *token;
int count =0;
int i =0;
memset(str, '\0', 50);
strcpy(str, (char*)content);
token = strtok(str, delimiter);
while( token != NULL )
{
count++;
if(count == 1)
{
strcpy(PlayerArr[i].Fname, token);
}
else if(count == 2)
{
strcpy(PlayerArr[i].Lname, token);
}
else if(count == 3)
{
PlayerArr[i].Singles= atoi(token);
}
else if(count == 4)
{
PlayerArr[i].Doubles= atoi(token);
}
else if(count == 5)
{
PlayerArr[i].Triples= atoi(token);
}
else if(count == 6)
{
PlayerArr[i].Homeruns= atoi(token);
}
else if(count == 7)
{
PlayerArr[i].At_Bats= atoi(token);
}
else if(count == 8)
{
PlayerArr[i].Slugging_Percentage= atof(token);
}
i++;
token = strtok(NULL, delimiter);
}
return 0;
}
Using tokenizer can also solve above problem