How to Use Functions

Once you have learned the basics of C programming, you will find yourself wanting to use functions. Functions are a way of organizing your code so that you can make your code reusable and easy to understand. See the following for a guideline on how functions work and when to use them.

Using Functions

Functions in C are essential for any programmer. Let’s say you want to calculate the length of a string (the number of characters in a string). One way to do this would be to create a counter variable, then loop through each character in the string using a while loop, incrementing the counter each time through the loop. This could look something like this:

int length(char *string_name) { int i = 0; while(string_name[i] != ‘\0’) { i++; } return i; }

This function takes one parameter, the name of a char array (a C-style string), and returns an integer representing the length of that string. You can call this function from anywhere in your program by simply calling “length()” with one argument (the name of the char array you would like to get the length of). Like this:

length(“Hello World”);

The above line would return 11 (the

How to Use Functions

Before you start writing functions, you need to be clear about where they should be used. Basically, if you’re repeating the same code more than once in your program, you should make a function for that code. Here’s an example:

Imagine we’re writing a program to calculate the area of a rectangle. We could call the variables length and width, and our formula would be length x width. In this case, length and width would be the parameters, and their product would be the return value. So our function would look like this:

float RectArea(float length, float width) {

return length * width;


In C++ programming language, functions are supposed to do one thing only (single responsibility principle). For example, if I have a function that returns the area of a circle but also prints out “Hello World” then this violates this principle because it is doing two things. A better design would be to create another function called PrintHelloWorld() which will print “Hello World”.

This guide is designed to help you learn to use functions in your programs. We’ll start with a look at what functions are and why they’re useful. Then we’ll look at how functions work and how to write your own.

Functions are one of the most fundamental building blocks of programming, so it’s important to understand how they work. If you haven’t read the first two tutorials in this series, I recommend doing that first:


Functions are one of the most important concepts in programming, and they are very useful. Functions allow you to reuse code and keep your code organized. Functions are also incredibly easy to use and learn. If you have the basics of C down, you should be able to easily start using functions.

A function is a small block of code that a programmer can create which performs a specific task. They allow programmers to organize their code more efficiently so it’s easier to read and understand.

Functions are a very powerful tool for structuring programs. It is therefore very important that you understand clearly how they work and how to use them properly.

Functions are used to structure programs in a logical way. The function starts at the top of the function code and executes the code line by line until it reaches the bottom. In this way the programmer can separate different parts of the program and still have them working together to execute the desired task.

You can use functions to:

– Calculate something based on given parameters (e.g. calculate_length(5,6)).

– Get a value from a user/user input (e.g. get_user_input()).

– Organize your program into logical units that can be easily maintained and reused (e.g. read_file(), write_file()).

When should I use functions?

There are no strict rules when to use functions but there are some guidelines you should follow:

– If code is repeated in your program it could be an indication that it would make sense to put it into a function as shown below:

Functions are a set of statements put together to perform a particular task. Functions take a input, perform computation on the input and generate an output.

Benefits of functions in C:

1. Prevent redundancy of code

2. Increase readability of code

3. Improves modularity and maintainability of code

4. Reusability of code

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