How Can I Initialize C Struct Members to Zero?

Default Initialization of C Struct Members

In a C struct, members are not automatically initialized to 0 by default. To initialize struct members to 0, there are several options:

Value Initialization

Using brace-enclosed empty braces { } assigns default values to all members:

Snapshot s = {};

Parent Struct Recursion

If a parent struct contains a sub-struct, value initialization of the parent struct will also initialize its sub-struct members to 0:

struct Parent { Snapshot s; };
Parent p = {}; // p.s.{x,y} will be zero

Constructor Initialization

If the struct has a constructor, members can be initialized in its parameter list:

struct Snapshot {
    int x;
    double y;
    Snapshot():x(0),y(0) { }
};
Snapshot s; // s.{x,y} will be zero

Value Initialization Using ()

Value initialization, indicated by (), initializes members regardless of their type:

struct Snapshot {
    int x;
    double y;
};
Snapshot s = {x(), y()}; // s.{x,y} will be zero

Note that value initialization is important for template structs, ensuring proper initialization for different types.

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