engleski

On explaining variable range in standard programming languages (to STEM students)

In addition to many specialised computing tools for solving different kinds of technical and mathematical problems, students in STEM fields are often required to develop and use their own solutions - often implemented as more or less complex programmes written in standard programming languages such as C/C++, Java, Python, Pascal and others. Depending on curriculums of lower stage education (secondary schools and high schools) and their personal interests and hobbies, those students may show different levels of knowledge related to programming skills. In our undergraduate courses (in electrical engineering and multimedia) we decided, based on quite pronounced divergence among students, to include full course for learning fundamentals of programming in C with some minor inclusion of C++ basics. In relation to other courses, for example computer architecture and digital electronics, we are always trying to give our students a wider perspective and somehow interconnect those fields. One of the first classes relates to the declaration of variables, with special notes about numeric variables (integer numbers in this case) and range limitations - the simple theory is not an issue, but when put in front of the real-world problem, students often somehow oversee those fundamental definitions. In this article we will present a simple function - calculation of factorials (direct multiplicative loop solution, not approximation expression) - and detect and depict a problem that appears due to limited range, or better to say, influence of bit- length of a certain integer type on obtaining proper results. Different kinds of variable types will be discussed, including mathematical explanation of result limits. The same function will be checked in a few programming languages in addition to C (Pascal among “standard old-school” languages and JavaScript and Python as other often used languages). Also, specialised, open-source and free, computing tool with its accompanying language, Scilab, will be used to check whether such tools give some better results out of the box. Comparison of results (calculation limits) will be given, with explanations. Some remarks about additional extension of integer type limits will be covered.

Programming, variable, range, integer, bit-length, education, C, Pascal, Python, JavaScript.

nije evidentirano