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Xiaobian to share with you what kinds of constants in the C language, I believe most people still do not know how, so share this article for your reference, I hope you have a lot of harvest after reading this article, let's go to understand it together!

1. literal constant

A literal constant is the simplest constant, as we take it literally. Here are some examples to help you understand:

//1. literal constant 100; //integer constant 3.14; //floating constant "abfdj"; //string constant 'w'; //character constant int a[100]; //where 100 is also a constant, it should be noted here that the number in [] must be a constant, we will use this 2, const modified constant variable later

Const variables have certain characteristics of constants, the most important of which is that const variables cannot be changed, but note that const variables are still essentially variables, but cannot be changed, just like static local variables whose life cycle changes, but the scope does not change. They are still local variables in essence, and the scope is still within the defined code block. In fact, there are some examples of this kind in computers. Instead of listing them here, let's look at these variables.

Here it can be seen that const-modified variables can no longer be modified. Here's how to show that const does not change the nature of the variable.

As we mentioned above, array [] must be constant, we put const variable a into [], compiler will give an error, so const variable is still essentially variable.

3.#define identifier constants

From this, we can get that #define modifies constants that cannot be modified (the first figure can be seen as unmodifiable, and Figure 2 can be seen as constants. As for the specific reasons, why the #macro definition will be like this in the future, we will have the opportunity to give you a corresponding explanation in the future. For now, we can remember it first.

Note: General #define definition constant name (in fact, this is not the definition of variables we usually understand, is a macro definition, there will be an opportunity to tell you later, today will not be described in detail) in capital letters, theoretically can be used in lowercase, but as a good programmer, I believe we can do this, although only a small detail, but also can reflect a programmer's self-cultivation, I hope you can notice.

4. Enumeration constants

From the above, it can be seen that enumeration types are indeed constants, but two points need to be noted. The first point is that the data values of enumeration types are generally upper case, such as MALE, FEMALE, SECRET in the figure. Although theoretically they can also be lower case, the specific reason why I emphasize them here is the same as above. The second point is that when enumerating type definitions, the separator in {} is a comma, and it is generally placed in unused lines as in the figure, which can make the code look more concise.

The above is "C language what kind of constants" all the content of this article, thank you for reading! I believe that everyone has a certain understanding, hope to share the content to help everyone, if you still want to learn more knowledge, welcome to pay attention to the industry information channel!

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