Why is dot-notation initialization not supported for structs in C ?

C Structure Initialization: An Alternative Approach

In C , unlike C, it's not possible to initialize structures using the dot notation shown below:

<code class="c++">struct address {
    int street_no;
    char *street_name;
    char *city;
    char *prov;
    char *postal_code;
};

// Invalid C++ syntax
address temp_address = { .city = "Hamilton", .prov = "Ontario" };</code>

This query raises several questions:

• Why is this initialization method not supported in C ?
• Is it due to technical or practical reasons?
• Are there alternative ways to improve readability in structure initialization?

Technical and Practical Reasons

Technically, there is no underlying limitation preventing the implementation of dot-notation initialization for structs in C . However, the C Standards Committee has chosen not to include this feature for several practical reasons:

• Consistency: C aims for consistency across different language features. Since dot-notation initialization is not available for other types (e.g., arrays), applying it to structs could lead to confusion.
• Type Safety: Dot-notation initialization bypasses type checking, potentially introducing errors if the member names or types are incorrect.
• Maintenance: Supporting this method would add complexity to the compiler and make it more difficult to maintain and evolve the language.

Alternative Approaches for Readability

To enhance readability, consider the following alternatives:

• Multi-line Initialization: Split the initialization onto multiple lines, with comments for each member:

<code class="c++">address temp_address = {
  0,  // street_no
  nullptr,  // street_name
  "Hamilton",  // city
  "Ontario",  // prov
  nullptr,  // postal_code
};</code>

• Initializer Lists: Use a constructor with an initializer list to initialize the members:

<code class="c++">struct address {
  address(int sn, char* stn, char* c, char* p, char* pc):
    street_no(sn), street_name(stn), city(c), prov(p), postal_code(pc) {}

  int street_no;
  char *street_name;
  char *city;
  char *prov;
  char *postal_code;
};

address temp_address(0, nullptr, "Hamilton", "Ontario", nullptr);</code>

These alternatives provide explicit and readable initialization while adhering to C 's type safety and consistency principles.

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