PROGRAMMING:Recursive call of function
Write for n! It's a good procedure. Requirements: write a function to achieve the value of the given n factorial. The main function is responsible for determining the value of N, calling the user-defined function, and outputting the calculation results.
###Input format:
Enter a value of any integer n.
###Output format:
If n = 0 or n = 1, then n= 1； If n < 0, output "given number < 0, no value! no value!” The result of the test.
###Input example:
Here is a set of inputs. For example:
```in
five
```
###Output example:
The corresponding output is given here. For example:
```out
5!= one hundred and twenty
```
answer：If there is no answer, please comment
###Input format:
Enter a value of any integer n.
###Output format:
If n = 0 or n = 1, then n= 1； If n < 0, output "given number < 0, no value! no value!” The result of the test.
###Input example:
Here is a set of inputs. For example:
```in
five
```
###Output example:
The corresponding output is given here. For example:
```out
5!= one hundred and twenty
```
answer：If there is no answer, please comment