JavaScript Function Examples: Calling and Defining

📚 Quick Study Guide

🔑 Function Definition:
• 💡A function is a block of code designed to perform a particular task.
• ✍️ A JavaScript function is defined with the `function` keyword, followed by a name, parentheses `()`, and curly braces `{}`.
• 💻 Syntax: `function functionName(parameters) { // code to be executed }`
📞 Function Calling:
• 📲 To *use* a function, you must *call* or invoke it.
• 🖱️ Calling a function executes the code inside the function.
• ✨ Syntax: `functionName(arguments);`
⚙️ Parameters vs. Arguments:
• 🧩 Parameters are listed inside the parentheses in the function *definition*.
• 🧪 Arguments are the *actual values* passed to the function when it is called.
↩️ Return Statement:
• 🎁 The `return` statement specifies the value a function returns.
• ➡️ After the `return` statement is executed, the function stops.

Practice Quiz

1. Which keyword is used to define a function in JavaScript?
   1. function
   2. method
   3. define
   4. procedure
2. What is the purpose of calling a function?
   1. To declare the function's name.
   2. To execute the code inside the function.
   3. To define the function's parameters.
   4. To return a value.
3. What is the difference between parameters and arguments?
   1. Parameters are the actual values passed when calling a function, while arguments are variables listed in the function definition.
   2. Arguments are the actual values passed when calling a function, while parameters are variables listed in the function definition.
   3. There is no difference; the terms are interchangeable.
   4. Parameters are used in function calls, while arguments are used in function definitions.
4. What does the `return` statement do in a function?
   1. It starts the function.
   2. It defines the function's name.
   3. It specifies the value a function returns and stops the function's execution.
   4. It calls another function.
5. Which of the following is the correct way to call a function named `greet` with an argument `"World"`?
   1. `greet = "World";`
   2. `function greet("World");`
   3. `greet("World");`
   4. `call greet("World");`
6. What happens if a function does not have a `return` statement?
   1. It will cause an error.
   2. It will return `undefined`.
   3. It will return `null`.
   4. It will return the function's name.
7. Given the function `function add(a, b) { return a + b; }`, what will `add(5, 3)` return?
   1. 5
   2. 3
   3. 8
   4. undefined