C: segmentation fault when running function from another file - c

Question

When ever i run this code, it works up until i get to the printf statement in my main function, thats when i get a segmentation fault error. so it will run like "enter how many numbers you want" 3 "Enter the numbers in the array" 1 2 3 array[0] = 1 array[1] = 2 array[2] = 3 segmentation error. Can you guys please tell me why im getting this error and how to fix it? thank you
//pathfinder.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "Vector.h"
int main()
{
Vector *V;
VectorRead(V);
printf("%d", V->item[0]);
return 0;
}
//Vector.h
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
typedef struct{
int *item;
int size;
} Vector;
void VectorRead(Vector *V) ;
void VectorRead(Vector *V)
{
int N;
printf("Enter how many numbers you want?\n");
scanf("%d", &N);
V = (Vector *)malloc(sizeof(Vector *) * N);
V->size = N;
V->item = (int *)malloc(sizeof(int *) * V->size);
printf("Enter the numbers that you want in your array\n");
int i = 0;
while(i < V->size && scanf("%d", &(V->item[i++])) == 1);
int j;
for(j = 0; j< V->size; j++){
printf("array[%d]=%d\n", j, V->item[j]);
}
}

Answer 1

This error has nothing to do with your code being in different files.
When you call VectorRead(), you are passing a pointer value. Inside that function, you are setting the local V to the return value of a call to malloc(). There is no way for that local V to return back to the caller.
You will need to do something to return the newly allocated value of V back to the caller. Changing your function to return a Vector * (instead of taking one as a parameter) would be a good approach.

Answer 2

Your local Vector, V, is not being modified when VectorRead() is called. Try instead accepting a Vector ** in your function:
void VectorRead(Vector **V)
and modify the function accordingly.
Or, since your function has no return value, and as #EOF points out in the comments, it is probably a better idea to not take a parameter, and simply return the Vector *:
Vector *VectorRead(void)