Dynamically allocating array of struct from file C - c

Question

I have a program that i am trying to write that will open a file named hw3.data, this file will contain a string, a float, an int, and a string on each line. Example: someword 5.4 200000 someword
I do not know the size of the file or the size of the strings within the file. I need to dynamically allocate at array of struct to store the info. I am fairly new to C and have looked over other various questions and articles however none of them really helped me grasp how to solve this.
I figured the best way to go about solving this was to first statically declare a structure. Read the file for the length and then take the information from the static struct and then dynamically allocate.
Here is my code thus far:
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
//Static Array of Struct
struct record{
char name[100];
float hp;
int size;
char color[30];
};
//getData from file
int getData(FILE*, struct record[], int currSize){
fp = fopen("hw3.data","r");
if (fp !=NULL){
printf("file Open");
while(3==fscanf(fp, "[^,],%f,%d,[^,]", records[i].name &records[i].hp, &records[i].size, records[i].color)){
currSizef++;
}
} else {
printf("failed");
}
return 0;
}
//First sorting function to sort by FLOAT value
//Second sorting function to sort by INT value
int main()
{
int currSizef=0;
struct record *records;
FILE* fp = NULL;
int choice;
//menu
do
{
printf("\t\tMenu\n");
printf("Options:\n");
printf("Input a number to select option:\n");
printf("1-Sort floats high to low\n 2-Sort floats low to high\n");
printf("3-Sort intergers high to low\n 4-Sort intergers low to high\n");
printf("5-Exit\n");
scanf("%d", &choice);
switch (choice)
{
case 1: /*Print high to low floats*/
break;
case 2: /*print low to high floats*/
break;
case 3: /*print high to low ints*/
break;
case 4: /*print low to high ints*/
break;
}
}while(choice !=5);
return 0;
}

Answer 1

You can try loading the data to a temporary record and use realloc to dynamically extend the data size.
NOTE: if NULL is passed to realloc then realloc will behave like the malloc function for the specified size.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//Static Array of Struct
typedef struct record{
char name[100];
float hp;
int size;
char color[30];
}RECORD;
void record_copy(RECORD *dest, RECORD* src) {
strcpy(dest->name,src->name);
dest->hp = src->hp;
dest->size = src->size;
strcpy(dest->color,src->color);
}
//LoadData from file
RECORD* LoadData(FILE* fp,int *size){
int i = 0;
RECORD temp;
RECORD *data= NULL,*tempptr = NULL;
while( fscanf(fp, "%[^,],%f,%d,%[^,],", temp.name,&temp.hp,&temp.size,temp.color)==4 ) {
if( (tempptr = (RECORD*) realloc( data, sizeof(RECORD) * (i+1) )) )
data = tempptr;
else
return (NULL);
record_copy(&data[i],&temp);
i++;
}
*size = i;
return (data);
}
void record_sort(RECORD *data, int size) {
int i,j;
RECORD temp;
for (i = 0 ; i < ( size - 1 ); ++i)
for (j = 0 ; j < (size - i - 1); ++j )
if( data[j].hp > data[j+1].hp ) {
record_copy(&temp,&data[i]);
record_copy(&data[i],&data[i+1]);
record_copy(&data[i+1],&temp);
}
}
int main() {
FILE *fp = fopen("<fileName>","r");
RECORD *data = NULL;
int i;
int size;
if( fp != NULL ) {
data = LoadData(fp,&size);
}
record_sort(data,size);
for(i = 0;i<size;i++) {
printf("%s:%f:%d:%s\n",data[i].name,data[i].hp,data[i].size,data[i].color);
}
free(data);
return 0;
}
with respect to sorting you can use any sorting algorithm to sort your record. I have given an example for that.