Predefined Macros
Predefined macros are built-in macros provided by the C++ preprocessor. They convey information about the code, such as the current line number, source file name, and compilation date. These macros are automatically defined by the compiler and can be useful for debugging and logging purposes.
The following are some commonly used predefined macros in C++:
- __LINE__: This macro expands to the current line number in the source code.
- __FILE__: This macro expands to the name of the current source file.
- __DATE__: This macro expands to a string that represents the date of compilation.
- __TIME__: This macro expands to a string that represents the time of compilation.
Example
In this example, __LINE__ is replaced with the current line number, __FILE__ with the source file name and __DATE__ with the compilation date. These can be handy for debugging and logging.
C++
// C++ program to illustrate the predefined macros #include <iostream> using namespace std; int main() { // Display the current line number and the source file // name cout << "This is line " << __LINE__ << " in file " << __FILE__ << "\n"; // Display the compilation date cout << "Compiled on " << __DATE__; return 0; } |
This is line 10 in file ./Solution.cpp Compiled on Nov 7 2023
Macros In C++
C++ is a powerful and versatile programming language that offers many features to enhance code flexibility and maintainability. One such feature is macros, which are preprocessor directives used for code generation and substitution. Macros are an essential part of C++ programming and play a crucial role in simplifying code, making it more readable and efficient. In this article, we will learn about the macros in C++.
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