John should use an If-Else statement to check if a number is even or odd. The If-Else statement evaluates a condition and executes different code blocks based on whether the condition is true or false. In this case, John can use the modulus operator (%) to check if the number divided by 2 leaves a remainder of 0 (even) or not (odd).

In C++, when both declaration and definition of a function are available but with different default argument values, the compiler selects the default values from the definition. This ensures consistency in behavior when the function is called from different parts of the code, as the definition takes precedence.

The use of the "goto" statement in C++ is generally discouraged because it can lead to spaghetti code, making the code harder to read and maintain. It creates unstructured jumps in the code, making it challenging to follow the program's flow. Therefore, it often degrades both readability and maintainability.

If none of the conditions in an if-else if structure are met, and there is no else clause, the program simply continues execution without executing any of the code blocks in the if-else if structure. This behavior is often desired when you have a series of conditions and you don't want any specific action when none of them is met.

The % operator, also known as the modulus operator, is used in C++ to determine the remainder of the division of one integer by another. For example, 5 % 2 equals 1 because 2 divides into 5 twice with a remainder of 1.

This codebase is following the Procedural Programming approach. In Procedural Programming, functions are often declared at the beginning of the code, and their actual implementations are provided later in the code. This approach promotes a step-by-step, imperative style of programming.

In a switch statement, cases are executed sequentially unless a 'break' statement is encountered. If Bob's program was executing the case for 'B' even after 'A' was satisfied, the most probable reason is a missing 'break' statement in case 'A'.

The cause of ambiguity in this scenario could be an ambiguous function call. When multiple overloaded functions have default arguments, the compiler might not be able to determine which function to call based on the provided arguments, leading to an error.

For a function to accept a variable number of arguments, it should use the keyword "varargs" (short for variable-length argument list). Varargs is used in C and some C++ code to create functions that can accept a variable number of arguments. This is often used in functions like printf(), scanf(), and other cases where the number of arguments can vary.

In C++, the "*" (multiplication) operator has higher precedence than the "&&" (logical AND) operator. This means that when evaluating expressions, the multiplication operator will be evaluated before the logical AND operator. Understanding operator precedence is crucial for writing correct and efficient C++ code.