Differences and comparison of advantages and disadvantages between C++ functions and macros

Functions are code blocks executed during runtime and can return results; macros are constants or code fragments expanded during preprocessing and cannot return results. Functions are easy to read, reusable, and have high code readability, but low efficiency; macro compilation has low overhead and excellent performance, but poor code readability and is difficult to debug.

The difference and advantages and disadvantages of C functions and macros

Overview of functions and macros

Function:Code A block that performs a specific task and returns a result.

Macro: The code name of a constant or other code fragment, which is expanded during the preprocessing stage.

Difference

Features	Function	Macro
Definition method	type function_name(params)	define MACRO_NAME expression
Execution	Runtime	Preprocessing time
Scope	Internal function	Macro location File
Return value	Can be returned	None
Parameters	Can Yes	No
Type checking	Yes	No
Efficiency	Lower than macros	Higher than functions

Advantages and disadvantages

Function advantages:

• Easy to read and maintain
• Can return results
• High code reusability

Function disadvantages:

• Compilation overhead is large
• Performance is lower than macros

Advantages of macros:

• Compilation Minimal overhead
• Excellent performance

Macro disadvantages:

• Difficult to debug
• Code readable Poor performance
• Unable to return results

Actual case

The following is a code example for comparing functions and macros:

// 函数
int sum(int a, int b) {
  return a + b;
}

// 宏
#define SUM(a, b) (a + b)

// 测试
int main() {
  int x = 10;
  int y = 20;

  int func_result = sum(x, y); // 函数调用
  int macro_result = SUM(x, y); // 宏展开

  std::cout << "Function result: " << func_result << std::endl;
  std::cout << "Macro result: " << macro_result << std::endl;

  return 0;
}

Output:

Function result: 30
Macro result: 30

Conclusion

Functions and macros are useful tools for code reuse. Functions are more suitable for scenarios that require return values, type checking, and high code readability. Macros are more suitable for scenarios that require extremely high performance and compilation efficiency.

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