Pointer storage array C

Preface

C The pointer of language is very easy and convenient after understanding , But before, I always left after compiling without paying attention warning, Study c++ Later, because of the stricter requirements for the use of pointers , The previous non-standard Pointer use slowly exposed .

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One 、 How to store arrays with pointers

Arrays and functions represent the first address of a string of data or an operation , Then it can be represented by a pointer . But the specific type , Before I use several levels of pointer, I just swallow it and run it . Because with *a Can be used to represent an array , Let me always think that two-dimensional arrays are completely usable **a To represent the , On the force button platform, this can often complete the problem , But when you run on the compiler, you can quickly find **a It cannot complete the function of two-dimensional array . This is because he missed a very important feature ： The pointer +1 Then pointing to the new location is different . Here we use a[3][4] give an example , The correct way of writing should be *a[][4], For the former +1 Span only sizeof(int) Distance of , While the latter is 4*sizeof(int), He can complete the function of two-dimensional array . But if you just store a two-dimensional array , Do you use int * Even char* It's all right , Because the type in front of them only represents them +1 Skip the distance , It doesn't affect them to store a first address .

Two 、 When the pointer is used C And C++ The difference between

Since any pointer can represent my array function, etc , Isn't my top talking nonsense ？ Note that the above usage, except for the formal writing, will warning Of , however C Language for the convenience of programmers want to easily find the address at any time , The type of address allowed by the program only determines the address every time +1 Distance crossed , There is no limit to what he saves .c++ Be more strict in this respect , You will find that your type does not match or the level of the pointer is wrong, and you can't run the code , It is very important to know the format of writing pointer correctly ！

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summary

We should learn later c++ Novices must pay attention to the norms of writing pointers at ordinary times , Writing well about the application of a pointer can get twice the result with half the effort , The type of pointer should also be flexibly adjusted , Make the whole program very flexible .