when are parameters created, how long do they exist, and when are they destroyed?
In computer programming, parameters are created when a function or method is defined. They are the variables that hold values passed to the function when it is called. The lifespan of parameters depends on the programming language and the specific context in which the function is called.
In languages like C and C++, parameters typically exist as long as the function is being executed. They are created when the function call is made and destroyed once the function execution is complete. This means that the parameters cease to exist once the function finishes its execution.
On the other hand, in languages like Python or JavaScript, the lifespan of parameters is limited to the duration of the function call. They are created when the function is invoked and destroyed when the function returns or finishes executing.
To see this behavior in action, let's consider an example in Python:
```python
def sum_numbers(a, b):
result = a + b
return result
x = 5
y = 10
z = sum_numbers(x, y)
print(z)
```
In this example, the `sum_numbers` function is defined with two parameters, `a` and `b`. When the function is called with the arguments `x` and `y`, the parameters `a` and `b` are created and initialized with the values of `x` and `y`. Within the function, `result` holds the sum of `a` and `b`. Once the `return` statement is encountered, the variables (`a`, `b`, `result`) are no longer accessible outside the function, and they are freed from memory.
In summary, parameters exist within the scope of a function call and are created when the function is invoked, live during the execution of the function, and are destroyed when the function returns or finishes executing.