Assignment - Functions

1. What is a function?
2. What is a function call?
3. What is a code block, and how does it relate to a function?
4. Create a function that takes a string as an argument and greets the user. For example, if the function is called with "John," the function should return "Hello, John!"
5. Create a function that takes a string as an argument and returns a string with the argument value in reverse. For example, if the function is called with the input "hello," the function should return "olleh." (Use a loop, not a method that does this in one step.)
6. What is a default argument, and how does it work?
7. What is the scope and lifetime of a variable?
8. What is a return value?
9. What is the return value of a function that does not have a return statement?
10. Given the following function, find mistakes in the code and explain what the function is supposed to do:

    function foo(x) {
        x * 2;
    }
    
    let x = 7;
    x = foo(x);
    console.log(x);

11. Given the following code, find and correct the mistake in the code:

    function bar(x = 8) {
        x += 1;
    }
    
    function foo() {
        bar();
        x *= 2;
    }
    
    let x = 7;
    foo(x);
    console.log(x); // x should change!

12. Given the following function, what is the return value of the function call foo(2)? Explain your answer.

    function foo(x) {
        if (x > 5) {
            return x;
        } else {
            return x + foo(x + 1);
        }
    }

13. Create a function that takes an array of numbers as an argument and returns the sum of the odd numbers in the array. (Use a loop, not a method that does this in one step.)
14. Create a function that takes a string as an argument and returns a boolean, true if string is a palindrome else false. A palindrome is a word that reads the same backward as forward. For example, if the function is called with "hello" it should return false, if the function receives "elle" it should return true, because elle backwards is also elle.