Why are Some Array Elements Initialized to Zero When I Assign a Default Value in C ?

Initialization of Array Elements with Default Value in C

Question:

Why does initializing an array with a non-zero value using the syntax below result in inconsistent values?

int array[100] = {-1};

Answer:

Using the syntax mentioned in the question,

int array[100] = {-1};

initializes the first element to the specified value (-1) and sets the remaining elements to 0 by default. To initialize all elements to -1, one can utilize the std::fill_n function from :

std::fill_n(array, 100, -1);

For C code, a manual loop is required to initialize all elements explicitly. Compiler extensions or implementation-defined behaviors may provide shortcuts, but relying on these is not recommended for portability.

Regarding Initialization Speed:

The default initialization method is generally not faster than explicitly initializing each element using a loop. However, the performance difference is typically negligible unless dealing with large arrays.

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