parameters arguments 形式参数 实际参数

 

parameter和argument的区别 – 笑遍世界 http://smilejay.com/2011/11/parameter_argument/

 

https://en.wikipedia.org/wiki/Parameter_%28computer_programming%29

 

For example, if one defines the add subroutine as def add(x, y): return x + y, then x, y are parameters, while if this is called as add(2, 3), then 2, 3 are the arguments. 

 

In computer programming, a parameter (often called formal parameter^[1] or formal argument) is a special kind of variable, used in a subroutine to refer to one of the pieces of data provided as input to the subroutine.^[a]These pieces of data are the values^[2][3][4] of the arguments (often called actual arguments or actual parameters) with which the subroutine is going to be called/invoked. An ordered list of parameters is usually included in the definition of a subroutine, so that, each time the subroutine is called, its arguments for that call are evaluated, and the resulting values can be assigned to the corresponding parameters.

Unlike argument in usual mathematical usage, the argument in computer science is thus the actual input expression passed/supplied to a function, procedure, or routine in the invokation/call statement, whereas the parameter is the variable inside the implementation of the subroutine. For example, if one defines the add subroutine as def add(x, y): return x + y, then x, y are parameters, while if this is called as add(2, 3), then 2, 3 are the arguments. Note that variables (and expressions thereof) from the calling context can be arguments: if the subroutine is called as a = 2; b = 3; add(a, b) then the variables a, b are the arguments, not the values 2, 3. See the Parameters and arguments section for more information.

In the most common case, call by value, a parameter acts within the subroutine as a new local variable initialized to the value of the argument (a local (isolated) copy of the argument if the argument is a variable), but in other cases, e.g. call by reference, the argument variable supplied by the caller can be affected by actions within the called subroutine (as discussed in evaluation strategy).

The semantics for how parameters can be declared and how the (value of) arguments are passed to the parameters of subroutines are defined by the language, but the details of how this is represented in any particular computer system depend on the calling conventions of that system.

 

 

 

Generic Types (The Java™ Tutorials > Learning the Java Language > Generics (Updated)) https://docs.oracle.com/javase/tutorial/java/generics/types.html

Type Parameter and Type Argument Terminology: Many developers use the terms "type parameter" and "type argument" interchangeably, but these terms are not the same. When coding, one provides type arguments in order to create a parameterized type. Therefore, the T in Foo<T> is a type parameter and the String in Foo<String> f is a type argument. This lesson observes this definition when using these terms.