C++ Functions Notes PDF

**Chapter 6 Notes: Functions in C++** **Key Concepts** 1. **Local Variables and Function Calls** - Local variables are allocated on the function's stack frame. - The stack frame is destroyed when the function returns, losing all local variable values. - A fresh set of...

**Chapter 6 Notes: Functions in C++** **Key Concepts** 1. **Local Variables and Function Calls** - Local variables are allocated on the function's stack frame. - The stack frame is destroyed when the function returns, losing all local variable values. - A fresh set of local variables is created on the next function call. 2. **Argument vs. Parameter** - **Parameter:** A variable declared in the function's definition (e.g., int x in void func(int x)). - **Argument:** The actual value passed to the function during a call (e.g., func(10)). 3. **Parameter Variables** - Defined in the function's header, inside parentheses. - Example: void func(int param) { }. 4. **Protecting Arguments from Modification** - Pass by value (default in C++) to create a copy. - Use const with references: void func(const int &x). 5. **Order of Arguments** - Arguments in a function call must match the order and types in the function definition. 6. **Returning Values** - Use return followed by an expression: return x;. 7. **Advantages of Modular Code** - Easier maintenance, readability, debugging, and code reuse. 8. **Static Local Variables** - Retain their values between function calls. - Useful for storing persistent data or counts. 9. **Passing Arguments by Reference** - Allows the function to modify the original variable. - Example: void swap(int &a, int &b). **Fill-in-the-Blank Concepts** 1. The **function header** shows the function name, return type, and parameter list. 2. A function that doesn't return a value uses the **void** return type. 3. Either a function\'s **prototype** or its definition must precede all calls to the function. 4. Values sent into a function are called **arguments**. 5. Special variables that hold copies of arguments are **parameters**. 6. Passing only a copy of an argument is called **pass by value**. 7. A **function prototype** eliminates the need for defining a function before calling it. 8. A **local variable** is defined within a function and inaccessible outside it. 9. **Global variables** are accessible by all functions and initialized to 0 by default. **True or False** 1. **True:** Functions should have names reflecting their purpose. 2. **False:** Function headers end with braces, not semicolons. 3. **True:** Function prototypes end with semicolons. 4. **True:** Programs always begin execution at main(). 5. **False:** Functions return to the point of the call, not necessarily main(). 6. **True:** Argument order in the call must match the parameter order in the function. 7. **True:** Parameter scope is limited to its function. 8. **False:** Function parameters only modify arguments if passed by reference or pointer. 9. **True:** Parameter names in prototypes are optional. 10. **True:** Local variables can have the same names as global variables. **Algorithm Workbench Examples** 1. **Example Call** void showValue(int quantity); showValue(10); 2. **Function for Half Value** double half(double number) { return number / 2.0; } 3. **Using a Function** int result = cube(4); // cube(int num) { return num \* num \* num; } 4. **Function to Multiply by Ten** void timesTen(int number) { cout \ 100); } **Common Errors in Functions** 1. **Invalid Void Function** void total(int value1, value2, value3) { return value1 + value2 + value3; } // Errors: Parameter types missing; void can\'t return. int total(int value1, int value2, int value3) { return value1 + value2 + value3; } 2. **Average Calculation** double average(int value1, int value2, int value3) { return (value1 + value2 + value3) / 3.0; } 3. **Default Arguments in Wrong Order** int area(int length = 30, int width = 10) { return length \* width; } 4. **Incorrect Reference Syntax** void getValue(int &value) { cin \>\> value; } **Chapter 7 Notes: Arrays in C++** **Key Concepts** 1. **Size Declarator vs. Subscript** - **Size Declarator:** Specifies the total number of elements an array can hold. Example: int values\[10\]; (size declarator is 10). - **Subscript:** Index used to access a specific array element. Example: values\[0\] (subscript is 0). 2. **Memory Usage** - Each element\'s memory size is determined by the data type. - Example: int values\[10\]; (if int is 4 bytes, the total memory used is 10 \* 4 = 40 bytes). 3. **Array Initialization** - Can be done with an initializer list: int values\[5\] = {1, 2, 3, 4, 5};. - Uninitialized elements are set to 0 if the array is static or global. 4. **Accessing Elements** - Array indexing starts at 0 and ends at size - 1. - Example: For int values\[5\] = {4, 7, 6, 8, 2};: - values\[0\] is 4. - values\[4\] is 2. 5. **Passing Arrays to Functions** - Arrays are passed by reference (as a pointer to the first element). - The function must also accept the array size to avoid out-of-range access. 6. **Two-Dimensional Arrays** - Declared with two size declarators: double sales\[8\]\[10\];. - Access elements using row and column indices: sales\[0\]\[1\]. 7. **Vectors (STL) vs. Arrays** - Vectors are dynamic, resizeable, and have member functions like size() and push\_back(). - Arrays have a fixed size and lack such flexibility. **Fill-in-the-Blank Concepts** 1. **Size Declarator and Subscript** - The **size declarator** specifies how many elements an array can hold. - The **subscript** is used to access specific elements. 2. **Initialization and Memory** - If an array is **partially initialized**, uninitialized elements are set to 0. - A two-dimensional array requires **two size declarators** for definition. 3. **Array and Function Relationship** - To pass an array to a function, pass its **name**. - A **two-dimensional array** passed to a function must specify the size of all dimensions except the first. 4. **Vectors** - A **vector** is a sequence container in the STL. - Use push\_back to add elements and pop\_back to remove the last element. **True or False** 1. **True:** Arrays cannot be resized once defined. 2. **False:** The first element of an array is accessed by the subscript 1 (it\'s 0). 3. **True:** Arrays do not perform bounds checking in C++. 4. **True:** An array can be partially initialized. 5. **True:** A two-dimensional array is like several arrays put together. **Examples and Algorithm Workbench** 1. **Accessing and Initializing Arrays** int numbers\[5\] = {1, 2, 3}; // numbers\[3\] and numbers\[4\] will be initialized to 0. cout \ 3. **Accessing Structure Members** - **Dot Operator (.):** Used for direct access. s1.name = \"John\"; - **Arrow Operator (-\):** Used when accessing members through a pointer. Student \*ptr = &s1; ptr-\name = \"Alice\"; 4. **Structure Initialization** - Structures can be initialized when declared: cpp Copiar código Student s2 = {\"Alice\", 102, 3.9}; 5. **Nested Structures** - Structures can have other structures as members. struct Address { string city; string street; }; struct Student { string name; Address addr; }; Student s; s.addr.city = \"New York\"; 6. **Arrays of Structures** - Useful for storing multiple records of the same type. Student classList\[3\] = { {\"John\", 101, 3.8}, {\"Alice\", 102, 3.9}, {\"Bob\", 103, 3.7} }; cout \