Let me introduce some general ideas before getting into the subject of programming. Perhaps you see programming as the use of some language that can be understood by men and computers. It is true, but it is not all the truth. Computers understand some very simple instructions that are very difficult to use by humans. We need instructions which afford the translation of general concepts into the instructions that computers can understand: C, FORTRAN, and Scilab are sets of commands which can be translated to machine code.
`The data declarations, structures and control statements, and other C language elements, are not for the computer's benefit. The computer can't tell the difference between a million random bytes and a real program. All the C language elements are designed to allow the programmer to express and organize his ideas clearly in a manner tailored to him, not to the computer'This quote from Oualline (Oualline, S.: `Practical C Programming') can be generalized to any language. A program is not only `algorithms' and `structures': it contains a vision of the topic approached and, in the formal level, it is also a form of communicating ideas between persons just like any other form of written text. In this sense, comments, names of variables or fragmentation of levels of functioning are important aspects of any program. The open source concept is not only a practical idea that improves the distribution of a program but it is also a useful tool to communicate ideas.
The ability to communicate with other persons and the creation of easily maintainable code is greatly augmented by writing a clear and consistent code.
Besides the introduction of commands from the prompt, Scilab has different possibilities of programming that we are going to describe briefly.