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Software applications (or apps) are the programs that we use on our tablets and smartphones. There are many different types of apps which allow us to do a great variety of things such as:

• checking the weather forecast
• creating our own music
• sending photos to friends in different countries
• translating writing from one language to another

Some apps that we use are versions of video games that we can play on a game console. Game consoles have more memory and access information quicker so the games can be more complex.

When games are turned into apps for smartphones and tablets, the programmers need to reduce the amount of information used in the game so it can be played on a smartphone or tablet.

They might decide to:

• reduce the number of levels in the game
• remove the animated sequences
• have fewer characters
• use less detailed graphics

They also need to change the way the game is controlled so it can work on a touchscreen device.

Many apps are created to help solve a problem.

When developers are designing new apps, they think about how a certain problem could be solved using a smartphone or a tablet device.

Apps have been created to help us solve problems such as:

• trying to remember which books to take to school
• checking who is at the front door before answering it
• being reminded to do household chores

When designing their app developers need to think about the way the information will be presented to the user. The screen and the way we use the app is called the interface.

The interface should reflect what we are using the app for.

An app that is designed to be fun might use colourful cartoon characters and have funny noises play when items are selected.

Apps that are designed to help people with health conditions would have a more formal interface. Here, silly sounds would be inappropriate. Different colours might be used to show the level of concern with recorded health data.

Before programming an app, a developer will think about the things that they want it do.

Sometimes, developers use pseudocode to do this.

Pseudocode helps people think about what they will need their code to do without actually writing the code.

Just like you might create a storyboard when making a film or animation, pseudocode can be shown in a similar way to explain to others what the app will do.

Apps are created by writing code. The most popular programming language to use for app programming is a text language called Javascript.

Javascript allows a programmer to write code that can be used on different types of smartphones and tablet devices regardless of the operating system they use.

The most popular operating systems for touchscreen devices are:

• iOS - created by Apple for iPhones and iPads
• Android - created by Google and used on many devices including Samsung, Nokia and Huawei

Sometimes a programmer might want to write an app that is only for one type of operating system.

In this case, they might use a different language such as Swift (for iOS) or Kotlin (for Android).

When writing a program for a specific operating system, you can make greater use of the device's functions like the position of the home button and how the long press is activated.

Some apps are called web apps. This means that they are used through the world wide web.

To access the app you open its URL on a web browser. You can then use the app within that page.

Web apps do not take up space in your computer's memory because all the information is stored on the website's server.

They can be used by any device that can connect to the world wide web. However, they cannot be used when the device does not have a connection to the internet.