When should I use `int[]` (arrays) over `int*` (pointers) in C/C ?

C/C int[] vs int* (Pointers vs. Array Notation): A Comprehensive Comparison

Introduction

In C and C , arrays and pointers can be utilized interchangeably to represent and access sequential data. However, these two notations imply certain differences that affect their usage. This article aims to elucidate these differences across all possible contexts.

Key Differences

1. Memory Allocation

While both arrays and pointers point to memory locations, their allocation mechanisms differ. Array declarations like int c[] = "test" allocate memory on the stack. Conversely, pointer declarations like int* c = "test" assign a pointer to a pre-allocated data segment (usually read-only).

2. Object Type

Arrays are objects of array type, which describes a contiguous set of elements of a specific member object type (element type). Pointers, on the other hand, are objects of pointer type, which describes a reference to an entity of a specific referenced type.

3. Accessing Elements

Arrays and pointers can both be used to access individual elements. However, array elements are accessed using the subscript operator [] (e.g., c[0]), while pointers use the indirection operator * (e.g., *c).

4. Array Boundaries

Arrays have well-defined boundaries that are known at compile time. Attempting to access elements beyond these boundaries leads to undefined behavior. Pointers, however, have no built-in boundary checks, allowing out-of-bounds access but potentially resulting in errors.

5. Pointers to Incomplete Types

Arrays of incomplete types cannot be declared in C/C , while pointers to incomplete types are allowed. This allows recursive structures to be defined using pointers, which is not possible with arrays.

6. Size Information

Arrays store the number of elements they contain, while pointers have no such information. This means that in some cases, the size of an array can be automatically determined by the compiler, while the size of a pointer must be explicitly specified.

7. Modifiability

Arrays and pointers can both be used to modify data. However, attempting to modify data pointed to by a constant pointer leads to undefined behavior.

Conclusion

While arrays and pointers can be used interchangeably in many cases, their underlying differences must be considered when choosing the appropriate notation. Arrays offer more robust and memory-safe access, while pointers provide greater flexibility and low-level control. A clear understanding of these differences is essential for writing efficient and error-free code in C/C .

The above is the detailed content of When should I use `int[]` (arrays) over `int*` (pointers) in C/C ?. For more information, please follow other related articles on the PHP Chinese website!