How does the data type of parameters in C++ function overloading affect the overloading?

The data type of parameters in function overloading affects parsing, and the matching process is based on type. Data type promotions and conversions may change the matching. The void type matches any parameter type. In practice, the appropriate overloaded function is called according to the parameter type to implement type-specific processing.

How the data type of parameters in C function overloading affects overloading

Introduction

Function overloading is the ability in C to create functions with the same name but different parameter lists. The data type of a parameter can significantly affect the resolution of function overloads.

Type matching

When an overloaded function is called, the compiler will match the most appropriate function based on the actual parameters. The matching process is based on the data type of the parameters.

Type promotion and conversion

Some data types in C can be promoted or converted to other types. This may affect the resolution of function overloads. For example:

int sum(int a, int b);
double sum(double a, double b);

int main() {
  sum(1, 2.5); // 调用 double 类型版本的 sum
}

In this example, the integer argument 1 is promoted to double, so the double type version of the sum function is called.

Special case: void

void The type represents no type. It can match any parameter type, but cannot be used as the return value type of a function.

void print(int a);
void print(double b);

void main() {
  print(1); // 调用 void(int) 类型的 print
  print(2.5); // 调用 void(double) 类型的 print
}

Practical case

Consider the following example:

int sum(int a, int b);
double sum(double a, double b);
float sum(float a, float b);

int main() {
  int i = 10;
  double d = 20.5;
  float f = 30.2f;

  std::cout << sum(i, i) << std::endl; // 调用 int 类型的 sum
  std::cout << sum(d, d) << std::endl; // 调用 double 类型的 sum
  std::cout << sum(f, f) << std::endl; // 调用 float 类型的 sum
}

This program will print the following output:

20
41
60.4

The output displays, according to The appropriate sum function is called based on the data type of the argument passed in.

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