Write a function that takes the time as three integer arguments (hours, minutes and seconds) and returns the number of seconds since the last time the clock “struck 12.” Use this function to calculate the amount of time in seconds between two times, both of which are within one 12-hour cycle of the clock.

In the realm of programming, particularly in C++, a function is akin to a structured block dedicated to performing a specific task. These modular units of code not only enhance readability but also facilitate code reuse and maintainability.

A function in C++ is declared with a return type, a unique identifier known as its name, and an optional list of parameters enclosed in parentheses. These parameters act as input variables specific to the function's scope. After declaring a function, you must define what it does within its body, enclosed by curly braces.

For the given exercise, C++ functions play a critical role. The 'time_since_struck_twelve' and 'seconds_between_times' functions are the building blocks that encapsulate the logic required to perform time calculations. By employing functions, we create a level of abstraction that allows us to focus on the larger problem without getting bogged down in the minutiae of the computational details.

Time conversion involves transforming units of time into different formats or scales. This is crucial in time calculations, particularly when we aim to compare times or calculate durations. For example, when we work with standard clocks, we typically see time represented in hours, minutes, and seconds.

In programming, it's often necessary to convert these into a consistent unit to perform arithmetic operations efficiently. In typical scenarios, seconds are the preferred unit because they can express any time duration without requiring fractions. In the exercise, we convert hours to seconds by multiplying by 3600 and minutes to seconds by multiplying by 60. The magic numbers '3600' and '60' are derived from the number of seconds in an hour and a minute, respectively. Hence, when performing these conversions, a solid understanding of the relationships between these units is vital.

Programming logic forms the brain of a code sequence, enabling a program to make decisions and execute instructions based on given criteria. It is the set of instructions that dictates the flow of control through a program.

Good programming logic is characterized by clarity, adherence to a specific task, handling various scenarios, and efficient execution. When writing programs, logical structures such as conditionals, loops, and function calls come into play to create more complex and functional code.

In the context of the exercise with time calculations, logic is employed to handle the conversion of input times to a common unit, account for the special case when the clock 'strikes 12', and compute the difference between two times with accuracy. It's these logical steps that ensure the program not only runs without errors but produces the correct output for an array of possible inputs.