问： Is there a difference between a "parameter" and an "argument", or are they simply synonyms?
Parameter 与argument有啥区别？
答：
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Argument is often used in the sense of actual argument vs. formal parameter.
The formal parameter is what is given in the function declaration/definition/prototype, while the actual argument is what is passed when calling the function — an instance of a formal parameter, if you will.
That being said, they are often used interchangeably, their exact use depending on different programming languages and their communities. For example, I have also heard actual parameter etc.
So here, x and y would be formal parameters:
int foo(int x, int y) {
...
}
Whereas here, in the function call, 5 and z are the actual arguments:
foo(5, z);
Argument 一般用作实际参数，而parameter 是概念性的。parameter是在定义的时候指定的参数，而argument 是实际带入这些参数的参数值。
比如 x 和 y 是参数parameters:
int foo(int x, int y) {
...
}
而实际调用时， 5 和 z 是 arguments:
foo(5, z);
—————-------------
Generally, the parameters are what are used inside the function and the arguments are the values passed when the function is called.
double sqrt(double x)
{
...
return x;
}
void other(void)
{
double two = sqrt(2.0);
}
Under my thesis, x is the parameter to sqrt() and 2.0 is the argument.
—————------------
They are often used interchangeably in text, but in most standards the distinction is that an argument is an expression passed to a function, where a parameter is a reference declared in a function declaration.
参考链接：
以一个 perl 实例为例：
构造函数里：
my $ref={"Owner"=>$owner,
"Price"=>$salary,
"Style"=>$style,
};
The key/value pairs are called the properties, or attributes, of the object. The values are passed in as arguments to the constructor.
实例方法（display)里：
foreach $key( @_ )
{
print "$key: $$self{$key}\n";
}
在主程序调用时：
$house->display(“Owner”,"Style");
The instance method is called with arguments.