How to use define

define usage: 1. Define constants; 2. Define function macros: 3. Define conditional compilation; 4. Define multi-line macros. For more information about the usage of define, you can read the article under this topic.

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How to use define

Detailed explanation of define usage

define usage: 1. Define constants; 2. Define function macros: 3. Define conditional compilation; 4. Define multi-line macros.

Oct 11, 2023 am 11:53 AM

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How to use define to define constants

Usage of define constants: 1. Define numeric constants, "#define PI value"; 2. Define string constants, "#define GREETING "string""; 3. Define expression constants, "#define MAX(a, b) ((a) > (b) ? (a) : (b))”.

Oct 11, 2023 am 11:57 AM

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define usage of function macro

The usage of define function macro: 1. Define a simple calculation macro, "#define SQUARE(x) ((x) * (x))"; 2. Define a macro with multiple parameters, "#define MAX(a , b) ((a) > (b) ? (a) : (b))"; 3. Define macros with complex expressions, "#define ABS(x) ((x) < 0 ? -(x ) : (x))”.

Oct 11, 2023 pm 12:00 PM

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defineHow to define conditional compilation

defineConditional compilation can be achieved using the `#ifdef`, `#ifndef`, `#if`, `#elif`, `#else` and `#endif` preprocessing directives.

Oct 11, 2023 pm 01:20 PM

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defineHow to define multi-line macros

define defines a multi-line macro by using `\` to divide `do { \ printf("%d\n", x); \ } while (0)` into multiple lines for definition. In a macro definition, the backslash `\` must be the last character of the macro definition and cannot be followed by spaces or comments. When using `\` for line continuation, be careful to keep the code readable and make sure there is a `\` at the end of each line.

Oct 11, 2023 pm 01:24 PM

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