Answer:
The programming language is not stated; However, I'll answer this question using 2 programming languages (Python and C++)
Comments are used for explanatory purpose
Python program starts here
def get_my_age(): Â #Declare function
   age = 21  #Assign value to age
   print(age)  #Print age
get_my_age() #Call function
#End of Program
C++ Programming Language starts here
#include<iostream>
using namespace std;
int get_my_age() //Declare Function
{
int age = 21; //Assign value to age
cout<<age; //Print age
}
int main()
{
get_my_age(); //Call Function
return 0;
}