What are 'macros' and 'constants' used for in C?

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Savitra

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Macros: Macros are defined using the #define preprocessor directive. They are not variables; instead, they are symbolic constants. Macros are replaced by their values at compile-time through a process called macro expansion. Macros can include code and perform text substitution. They are processed...
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Macros: Macros are defined using the #define preprocessor directive. They are not variables; instead, they are symbolic constants. Macros are replaced by their values at compile-time through a process called macro expansion. Macros can include code and perform text substitution. They are processed by the preprocessor before the actual compilation of the code. Macros can be used to create reusable code snippets, conditional compilation, or to define constants with complex expressions. Constants: Constants are variables that are declared as read-only, and their values cannot be changed during the program's execution. In C, you can define constants using the const keyword. These are typically used for values that should not change throughout the program. Constants are stored in memory, and their values are accessed like regular variables. read less
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The const keyword causes the identifier size to be allocated in the read-only memory. This means that the value of the identifier can not be changed by the executing program. MACROS are efficient than the const statements as they are not given any memory, being more Readable and Faster in execution!
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