How to use flexible arrays in C language

This article mainly shows you "how to use flexible arrays in C language". The content is easy to understand and clear. I hope it can help you solve your doubts. Let me lead you to study and learn the article "how to use flexible arrays in C language".

Define

Resizable array

Defined as an array of 0 or no size in the last element of the structure

Characteristics

1. The flexible array in the structure must contain at least one other member.

The structure body size returned by 2.sizeof does not contain the memory of the flexible array.

3. Structures containing flexible array members use the malloc () function to dynamically allocate memory, and the size of the allocation should be larger than the size of the structure to accommodate the expected size of the flexible array.

Specific use case

There is also a general way to implement a resizable array:

But flexible arrays have the following advantages in comparison:

1. Facilitate memory release. If memory is allocated twice, it needs to be freed twice. If our code is given to someone else in a function and returns the entire structure, the user can call the function free to release the structure, but does not know that the members of the structure body also need to be released by free.

two。 It helps to improve the access speed, and continuous memory allocation is beneficial to improve the access speed and reduce memory fragmentation.

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