Performance impact of C++ function overloading and rewriting

Function overloading is resolved at compile time and has no impact on performance; function rewriting requires dynamic binding at runtime, which introduces a small amount of performance overhead.

The performance impact of C function overloading and rewriting

In C, function overloading and function rewriting are two different concepts , they have different effects on the performance of the program.

Function overloading

Definition:
Overloading refers to multiple functions with the same name but different parameter lists.

Performance impact:
Function overloading is resolved at compile time, so it will not have any impact on the execution performance of the program.

Practical case:

int max(int a, int b) {
  if (a > b) {
    return a;
  } else {
    return b;
  }
}

double max(double a, double b) {
  if (a > b) {
    return a;
  } else {
    return b;
  }
}

int main() {
  int a = 10;
  int b = 20;
  cout << "最大整数值：" << max(a, b) << endl;  // 调用重载的 max(int, int) 函数

  double c = 10.5;
  double d = 20.5;
  cout << "最大浮点值：" << max(c, d) << endl;  // 调用重载的 max(double, double) 函数
}

Function rewriting

Definition:
Rewriting means in a subclass Redefine the function in the parent class.

Performance impact:
Function rewriting requires dynamic binding at runtime, so it will introduce some additional overhead. However, this overhead is usually small and can be ignored in most cases.

Practical case:

class Base {
public:
  virtual int sum(int a, int b) {
    return a + b;
  }
};

class Derived : public Base {
public:
  int sum(int a, int b) override {
    return a + b + 1;  // 重写 sum() 函数，在原有基础上加 1
  }
};

int main() {
  Base base;
  Derived derived;

  int result1 = base.sum(10, 20);  // 调用父类 Base 的 sum() 函数

  int result2 = derived.sum(10, 20);  // 调用子类 Derived 的重写后的 sum() 函数
}

Conclusion

In general, function overloading will not affect the performance of the program, while function rewriting will introduce Some additional overhead. When choosing to use function overloading or function rewriting, developers should weigh the performance impact and other factors, such as the readability and maintainability of the code.

The above is the detailed content of Performance impact of C++ function overloading and rewriting. For more information, please follow other related articles on the PHP Chinese website!