There is also a functional software size measurement methodology, which is based on the assumption that the productivity of software development is somehow related to the functionality. Areas of functionality that are taken into account are called information domain values, some of which are listed below:

• Number of user inputs – counting the number of user entries. It takes into account each user input that presents the user with different information related to the application. Inputs must be separated from requests that are counted separately.
• Number of user outputs – counting the number of user outputs. Each user output, which provides the user with different information from the application, is taken into account. In this context, conclusions are understood as reports, screens, error messages, and the like. Individual data elements within the reports are not separately calculated.
• Number of user requests – the request is defined as an interactive input that causes immediate response of the software – it generates an interactive output.
• Number of files – each logical main file (namely, logically grouped data, which can be part of a large database consisting of separate files) is counted.
• Number of external interfaces – all machine-readable interfaces (for example, data files that are stored on some media so that to be transferred to other systems) are taken into account.

Is behavior of your mobile app correct? Does it run smoothly on popular devices? If you think that the program needs to be examined since it has performance bottlenecks it is recommended to use the services of mobile application testing companies.

Let us briefly consider the first stage of the two-stage process of counting functional points (FP). Stage 1 is started by the actor who has experience in conducting a functional points analysis. The actor must answer the questions contained in the special questionnaire using the numbers indicated in the questionnaire header. After receiving the answers to all 14 questions of the questionnaire, it is necessary to add all the numbers representing the answers and transfer the received amount to the next step.

In stage 2, you will need to multiply these numbers by the corresponding weights, sum up the received results and put the amount in the “Total Amount” field according to the instructions. As the factor SUM (F,), it is necessary to substitute the sum of the complexity refinement coefficients obtained in stage 1.

The functional point is a weighted index metric type. It is intended to change the functionality of the software package, as the end user sees it.