2 Some Fundamentals
2 Some Fundamentals
THIS CHAPTER DESCRIBES SOME FUNDAMENTAL TERMSthat you must understand before
you can learn how to program in C. A general overview of the nature of programming
in a higher-level language is provided, as is a discussion of the process of compiling a
program developed in such a language.
Programming
Computers are really very dumb machines indeed because they do only what they are
told to do. Most computer systems perform their operations on a very primitive level.
For example, most computers know how to add one to a number or how to test
whether a number is equal to zero.The sophistication of these basic operations usually
does not go much further than that.The basic operations of a computer system form
what is known as the computer’s instruction set.
To solve a problem using a computer, you must express the solution to the problem
in terms of the instructions of the particular computer. A computer programis just a col-
lection of the instructions necessary to solve a specific problem.The approach or method
that is used to solve the problem is known as an algorithm.For example, if you want to
develop a program that tests if a number is odd or even, the set of statements that solves
the problem becomes the program.The method that is used to test if the number is even
or odd is the algorithm. Normally, to develop a program to solve a particular problem,
you first express the solution to the problem in terms of an algorithm and then develop
a program that implements that algorithm. So, the algorithm for solving the even/odd
problem might be expressed as follows: First, divide the number by two. If the remainder
of the division is zero, the number is even; otherwise, the number is odd.With the algo-
rithm in hand, you can then proceed to write the instructions necessary to implement
the algorithm on a particular computer system.These instructions would be expressed in
the statements of a particular computer language, such as Visual Basic, Java, C++, or C.