What does *& mean in c++

The & operator sequence in C means to first dereference a pointer and then take its address, similar to &x, where & is the address operator and is the dereference operator. The specific operations include: first dereferencing the pointer &x to get the value of the variable it points to, and then taking the address of the value to get the value of &x. Usage scenarios include passing pointers to pointers, manipulating arrays of pointers, and navigating in multi-level pointer structures. Note that & is different from &&, which is a logical operator used to compare boolean values, and you should avoid creating dangling pointers when using &.

The meaning of &* in C

The &* in C is an operator sequence that represents the A pointer is dereferenced and its address is taken.

Decomposition:

• &: Take the address operator and return the address of a variable or expression.
• *: Dereference operator, returns the value of the variable pointing to the variable address.

Specific operation:

1. Suppose we have an int type variable x, whose address is &x.
2. &x is equivalent to first dereferencing &x (i.e. &x) to get the value of x.
3. Then take the address of the value of x and get the value of &x. Therefore, &*x is equal to &x.

Usage scenarios:

&* Mainly used when data needs to be accessed in a more precise way than ordinary pointers, for example:

• Passing pointers to pointers (double pointers)
• Manipulating arrays of pointers
• Navigating in multi-level pointer structures

Example:

int** p; // 双重指针
int* q = &*p; // q 指向 p 指向的变量
*q = 10; // 通过 q 修改 p 指向的变量

Note:

• &* is not the same as &&. The latter are logical operators used to compare Boolean values.
• Be careful when using &* to avoid creating dangling pointers, i.e. pointers to freed memory.

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