Thread: Creating Dynamic Structure in C

Some thoughts

Code:

typedef enum {
    isInt,
    isString,
    isDouble,
} data_et;

typedef struct field_st_tag {
    char                *fieldName;
    data_et              dataType;
    struct field_st_tag *next;
} field_st;

typedef struct data_st_tag {
    struct field_st_tag *field; /* what describes this field */
    union {
        int     iValue;
        char   *sValue;
        double  dValue;
    } u;                        /* all possible data types */
    struct data_st_tag  *next;  /* the next field */
} data_st;

typedef struct data_row_st_tag {
    struct data_st_tag      *row;   /* first field on this row */
    struct data_row_st_tag  *next;  /* the next row */
} data_row_st;

So you would read the file, and create a linked list of fields.
For StudentName:string, StudentAge:int, you would allocate and initialise
two nodes of a linked list
{ "StudentName", isString },
{ "StudentAge", isInt }

You would then read the data file one record at a time, and then walk
your fields list to decide what type each record field should be.
Allocate a data_st and initialise it with the correctly converted result.

Use data_row_st to build up a linked list of linked lists of all your data.