Programming itself is prettycomplicated. To begin with at least that all actions should be spelled out step by step. But, along with such a need, there are a number of possibilities that significantly facilitate the achievement of the task that should be performed by programming ("Pascal", "C", "Assembler" - no matter what language is used). One such tool is the creation of cycles.
Importance of cycles in programming
What is the cycle?Why is it necessary and what benefits does the programmer get when using it? The cycle is an important structural component of programming, which allows you to automate the execution of a certain number of actions, provided that the established parameters are observed. So, the simplest example of a loop's work is the rendering of a certain number to a power. There is no need to register the rows until it is enough, because the technician can do everything automatically with his help. In practical implementation, cycles can also save a lot of time and effort, because when using a loop, there is no need to write code for every action. It is enough to enter the variables to be replaced and run the implementation. But how is the circuit constructed? Or even a few? Themselves of the implementation of the cycle is quite a lot - information on the whole book about programming, "Pascal" we will consider or "Assembler". Therefore, for purely informational purposes, we offer to disassemble the theoretical scheme of the two most popular in use:
- A cycle with a postcondition.
- Cycle with precondition.
All the rest are to a large extent theirvariations and particular cases, therefore, they need to be considered in certain contexts and when specific goals are achieved. In the meantime, we turn to the most popular. What is the difference between cycles with precondition and postcondition? Here is a loop with a precondition:
while "condition" do "program code"
The general theoretical basis of the cycle with a postcondition
This is a form of writing code whenA loop operator with a postcondition of execution stands after the body. At first sight it may seem strange: indeed, why put the circumstance of execution after the program code? But there is nothing strange here: the peculiarity of this form is that the code will be executed regardless of whether the conditions of execution are met or not. But only once. Then they will check whether everything is as it should be, or not. And in the absence of proper conditions, the body of the cycle will be ignored. This is a very important and useful feature, which has a cycle with a postcondition. On an example of what was it told and where you can see the practical implementation of the painted here? Here is an example of a loop with a postcondition:
repeat
"Program code"
until "Condition"
The general theoretical basis of the cycle with a precondition
Но самым популярным вариантом является именно this. Its peculiarity consists in the fact that execution of the condition is necessary for execution, without this the code will never be executed. Typically, the program code is very large, and its activation will negatively affect the performance of the computer. Therefore, a rather clever plan is used: most parts of the code are placed in cycles or in general separate classes, to which the reference goes at the right time. The rest of the time this code is, but not used by the computer. This scheme allows you to save processor power for the execution of the program itself or other programs.
Practical implementation in various programming languages
A few words about the practical effectiveness of cycles.It should be noted first of all, saving time, both for the user and for the programmer. The second one already said why this is so, so a couple of words should be said about the client. The fact is that the breakdown into separate parts allows the software to load faster and work, and, accordingly, the user will only be happy to use such software. And this approach, when the code is stored in a cycle or a separate class (which are often called from the body), and allows you to ensure the effectiveness of the work. In addition, you should record the speed of writing to individual memory locations. So, if everything had to be done manually, it would be necessary to bypass each and in it to do the corresponding record. A cycle allows you to reduce the need to do everything yourself or even dozens of times. And it removes the human factor, which can lead to the need to search for hours of problem code.
Conclusion
So, summing up everything written, you cansay that a cycle with a postcondition or precondition allows us to save in the most convenient way without losing quality. And when writing complex programs, he is one of the best friends of the programmer, helping him to make the code more easy to execute and when reading. Therefore, when writing your code, do not hesitate to use a cycle with a postcondition or precondition - they are created specifically to facilitate the process of creating software, and it will work against yourself - not to take advantage of this opportunity.
