C++ error: Not a pointer type, how to solve it?

C is a very powerful programming language, but various problems will inevitably arise during the process of writing code. Among them, a common problem is the "not pointer type" error. This problem usually occurs when using pointers and may cause an exception or crash in the program. This article will explore the causes and solutions to this problem.

1. Why is the error "not a pointer type" reported?

In C, pointers are a very common data type. They are often used to store and manipulate data in memory, especially arrays. The characteristic of a pointer is that it stores the address of a variable or object in memory, so that the program can access the variable or object through the pointer.

When the error "not a pointer type" is reported, it is usually because we operate a variable or object of a common type as a pointer, causing an error in the program. For example, the following code:

int x = 10;
*x = 20;

In this code, we operate x as a pointer, but x is actually a variable of type int, so an error "not a pointer type" will be reported.

2. How to solve the "not pointer type" error?

1. Check the variable type

When the error "not a pointer type" is reported, first check the location where the error occurs and confirm which variable is mistakenly used as a pointer. Then, confirm whether the variable is a pointer type. If it is not a pointer type, you need to modify it to make it a pointer type.

For example, the above code can be modified as:

int x = 10;
int *p = &x;
*p = 20;

In the modified code, we define a pointer variable p, assign the address of x to it, and then use the pointer p to Modify the value of variable x.

2. Check pointer operation

In addition, be careful when operating pointers. Common errors in pointer operations include:

(1) Uninitialized pointer

The pointer must be assigned a value after being defined. If it is used without assignment, the program will experience an exception or crash.

(2) Release the released pointer

If a piece of memory has been released, but we are still using the pointer pointing to it, the program will also experience an exception or crash.

(3) Out-of-bounds access pointer

When operating an array, be careful not to access out-of-bounds, otherwise it will cause an exception or crash in the program.

The above problems may lead to "not a pointer type" error, so be careful when operating pointers.

3. Conclusion

"Not a pointer type" is one of the common errors in C, which usually occurs when using pointers. To solve this problem, we need to double-check that the variable types and pointer operations are correct. At the same time, you should also pay attention to following good programming habits. If some operations may cause an exception or crash in the program, these operations should be avoided as much as possible.

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