Question

I am writing a C project with pointers and structs, and right now facing this problem:
There is a structure

struct Customer
{
    char Name[80];
    char Address[40];
    int ID;
    int Pnumber;
};

and I am gonna make a dynamic array of this structs with *line_count* number of members. I use this code, but it crashes a program:

struct Customer* ph;
ph = (struct Customer*)malloc(line_count * sizeof(struct Customer));

What am I doing wrong?

Answer 1

Good:

struct Customer* ph;
ph = (struct Customer*)malloc(line_count * sizeof(struct Customer));

Better:

struct Customer* ph =
  (struct Customer*)malloc(line_count * sizeof(struct Customer));
if (!ph) {
  <<error handling>>
  ...

But frankly, it sounds like the problem is elsewhere in your code.

There’s nothing fundamentally wrong with your malloc().

Maybe “line_count” is bogus, maybe “malloc()” is failing (in which case, it should return “NULL”) … or maybe you’re accessing the struct incorrectly and/or failing to initialize it correctly.

A stack traceback of the actual crash would be very useful.