Why functions are important in programming

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Learn more about how FutureLearn is transforming access to education. Learn more about this course. Using functions This step builds on the information provided in the video in the previous step. This step builds on the information provided in the video in the previous step. Want to keep learning? This value is referred to as the actual parameter or argument.

The parameter list refers to the type, order, and number of the parameters of a function. Parameters are optional; that is, a function may contain no parameters. While creating a C function, you give a definition of what the function has to do. To use a function, you will have to call that function to perform a defined task. If you are clear about functions in C programming, then it is easy to understand them in Java as well. Java programming names them as methods , but the rest of the concepts remain more or less same.

Following is the equivalent program written in Java. Once again, if you know the concept of functions in C and Java programming, then Python is not much different. Computer Programming - Functions Advertisements. Previous Page. For example, if you wrote a function to read in lots of numbers from a text file and calculate the mode, you wouldn't need to know how it works to use it.

As long as you knew that the function expects a text file filled with numbers as input and outputs a number as the result, you could use it in any program without much trouble. But this isn't the only way that functions encapsulate code. They also allow programmers to cleanly divide their code into segments. While your main function might only have a few dozen lines of code, it could call multiple functions and perform complex operations through them.

This is the core of object-oriented programming. Plus, it helps split up large programs into smaller pieces so multiple people can work on them. Chances are that when you write some code to perform a task, you'll use it more than once in your program. Copying and pasting the needed code into multiple places is a bad idea. Not only does it add more complexity to your program, but it introduces more places for something to go wrong. If you change something in the original block, you have to remember to re-paste it everywhere else.

Functions eliminate this problem. They make it easy to reuse code anywhere else in your program. Once you've defined a function, you can call it anytime and be sure that it will run the same way. This saves time and reduces complexity, which are two welcome qualities for a program.

At many companies today, the functions one programmer writes may be used by others in the company in other projects. Since functions stand on their own, they're very portable. Reusing them where appropriate cuts down on duplicate work, makes more efficient use of programming resources, and helps with developing standards across a company.

Most programmers know the pain of trying to debug spaghetti code: a tangled, confusing mess that's nearly impossible to follow as it has little structure.

Without clear functions, programs jump all over the place. This makes it hard to debug, and a massive pain for someone coming in fresh to understand. With everything clearly divided into functions, programmers can use unit tests to confirm that these functions work as they should.