read data from file - c

Question

How to read the data from a file to a structure?
I have a structure like
struct data
{
char name[20];
int age;
};
In file student_info.txt I have
ravi 12 raghu 14 datta 13 sujay 10 rajesh 13
and so on with many other names with ages. How can I read this from file to the structure data?
Reading this name and age should be a loop i.e for the first time I will read 'ravi' and '12', then I should pack this data in the structure and will pass the structure to a function as soon as the structure is set. It should come back to the file and read 'raghu' and '14' again pack the structure with this data, and this should be in a loop till I read all the data from the file
Can anyone please tell how to implement the logic?

Answer 1

The approach is:
Create an instance of an array of your struct, a file pointer for file access, and a counter variable
Open the file stream using the file pointer - check that it has been successfully opened. The file pointer will point to NULL if fopen() has failed
Read the data into the struct array using a loop. fscanf() returns the number of successful 'matches' with its format string - here it will be 2 (use this for the loop condition)
Close the file
An example of the code:
#include <stdio.h>
#define FILENAME "student_info.txt"
#define MAX_NO_RECORDS 50
struct data
{
char name[20];
int age;
};
int main(void)
{
/* Declare an array of structs to hold information */
struct data StudentInfo[MAX_NO_RECORDS];
/* Declare a file pointer to access file */
FILE *s_info;
int student_no = 0; /* holds no. of student records loaded */
/* open the file for reading */
s_info = fopen(FILENAME, "r");
/* Check if an error has occured - exit if so */
if(s_info == NULL)
{
printf("File %s could not be found or opened - Exiting...\n", FILENAME);
return -1;
}
printf("Loading data...\n");
while(fscanf(s_info, "%19s %i", StudentInfo[student_no].name, &StudentInfo[student_no].age) == 2)
{
/* refer to records with index no. (0 to (1 - no. of records))
individual members of structure can be accessed with . operator */
printf("%i\t%-19s %3i\n", student_no, StudentInfo[student_no].name, StudentInfo[student_no].age);
student_no++;
}
/* after the loop, student_no holds no of records */
printf("Total no. of records = %i\n", student_no);
/* Close the file stream after you've finished with it */
fclose(s_info);
return 0;
}

Answer 2

You just need to read data from this file and split that string based on some criteria. as your file is not properly formatted it would be difficult for you to parse data.
In your current scenario your file contain only first name and a digit you can easily parse this by detecting a Space Character in your string. but this could lead a problem if any of your name contains a space.
First of all separate each pair of word by some character such as : or ; or a tab or line break.
then between each separated string split it by space and then read all content of file in a char array then from that array try to find that special character which indicates one record.
Separate each record in a different char array then for each generated array again and then split it based on space char and load in your struct
This is just for explanation, original implementation may be different,
Student std = {first string, second integer};
Hope that document solves your problem http://www.softwareprojects.com/resources//t-1636goto.html