Thread: Help in reading from file using fgets with array struct.

Hello my dears,
I have a problem regarding to reading from a file.
The problem is that I have 4 lines in the text file, the first is the IDs of employees, and the second line is their names, so I want to read it and sort it inside an array struct, but this attached code is for the first two lines, because the code works for the last two lines perfectly. I watched many concepts of reading from files and about fgets but I didn't find anything useful.

Code:

    FILE*in;    char tempNames[8];
    char *namesLine;
    int i;
    in=fopen("employees.txt", "r");
    employee_record AR[8];
        for (i=0; i<8; i++){
            fscanf(in, "%d", &AR[i].e_num);
        }fgets(tempNames, 8, in);
        namesLine=strtok(tempNames, " ,;");
        i=0;
        while (namesLine!=NULL){
            strcpy(AR[i++].name, namesLine);
            namesLine=strtok(NULL, " ,;");
        }
        for (i=0; i<8; i++)
            printf("%d %s\n", AR[i].e_num, AR[i].name);

File's data:

111111 222222 333333 444444 555555 666666 777777 888888
Sami;Mohammad Kamal,Waleed Maryam;Bayan Ahmad,Jaber

That what I get when I run the compiler:

111111

222222 └i
333333 └i
444444 ╝>╜┘
555555 Ç
666666 ╠i
777777 πnàvΦ>╜┘α@
888888 ╠ a

Don't mix fscanf with fgets. Use fgets to read line by line. Parse the first line with sscanf; parse the second line with strtok.

tempNames, at just 8 characters, doesn't cut it for reading a line. I would declare:

Code:

char buffer[BUFSIZ];

You don't need a for loop that just runs once, so simplify by getting rid of that extra loop.

How can I use sscanf for the first line which is a integer data? Also, I really don't know how to read line by line by using fgets.
If you could give me few hints about buffer since I don't know it.

Originally Posted by amohammed63

How can I use sscanf for the first line which is a integer data?

If it is expected that there is going to be 8 employee IDs, then just do one sscanf call with a suitable format string to get all 8 at one go. If not, you might want to parse the line into string tokens using strtok instead, then parse each token using sscanf or strtol, keeping track of the number of IDs for the next line.

Originally Posted by amohammed63

Also, I really don't know how to read line by line by using fgets.

It is just two lines, i.e., two fgets calls.

Originally Posted by amohammed63

If you could give me few hints about buffer since I don't know it.

You use it to store the line read.

Originally Posted by laserlight

If it is expected that there is going to be 8 employee IDs, then just do one sscanf call with a suitable format string to get all 8 at one go. If not, you might want to parse the line into string tokens using strtok instead, then parse each token using sscanf or strtol, keeping track of the number of IDs for the next line.

Yeah it's known that the line contains 8 IDs.
This code keeps reading the first ID

Code:

fgets(buffer, BUFSIZ, in);    for (i=0; i<8; i++){
        sscanf(buffer, "%d", &AR[i].e_num);
    }

or should I do this way
sscanf(buffer, "%d %d %d ....", AR[0].e_num, AR[1].e_num, AR[2].e_num, ....);?

Also the same problem with the second line, it keeps reading the first name

Code:

#include <stdio.h>
 
int main() {
    char buffer[1024] = "12 123 1 1234 21 2 321 32\n";
    int n[8];
 
    char *pbuf = buffer;
    for (int i = 0, pos = 0; i < 8; ++i)
        sscanf(pbuf += pos, "%d%n", &n[i], &pos);
    
    for (int i = 0; i < 8; ++i)
        printf("%d\n", n[i]);
 
    return 0;
}