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In C, function parameters can be set to default values, simplifying function calls and improving code readability. Additionally, C 11 introduces named parameters, which enhance code readability and flexibility by allowing parameter values to be specified using parameter names at function call time: Default parameters: Use the equal sign (=) to specify parameter default values. Named parameters: Use a colon (:) to separate the parameter name and value to specify the parameter name when the function is called.
In C, function parameters can have default values, which can simplify function calls and make the code more Easy to read. Additionally, C++11 introduced named parameters, allowing parameter names to be specified at function call time.
To set a default value for a function parameter, follow the parameter type with an equal sign (=) and a default value. For example:
int sum(int a, int b = 0) { return a + b; }
In this example, the default value of the b
parameter is 0. If a value for b
is not specified when calling the function, the default value of 0 will be used.
Advantages:
C 11 introduces named parameters, allowing parameter values to be specified by their names when a function is called. The syntax is to use :
to separate parameter names and values. For example:
int sum(int a, int b = 0) { return a + b; } int main() { int result = sum(b: 5, a: 3); // 使用命名参数 return 0; }
In the above example, the result
variable will contain 8 because the a
parameter is set to 3 and the b
parameter is specified via a named parameter is 5.
Advantages:
Consider a function that calculates the area of a circle:
double calcArea(double radius) { return 3.14159 * radius * radius; }
Using default parameters, we can allow the radius
parameter to have a default value 1.0:
double calcArea(double radius = 1.0) { return 3.14159 * radius * radius; }
Now we can call functions with default values or override them with named parameters if needed:
double area1 = calcArea(); // 使用默认半径 1.0 double area2 = calcArea(radius: 5.0); // 使用命名参数指定半径
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