What is computer science?
Computer science is, of course, the science of studying computers. It is the study of
computation and information processing, involving hardware, software, and even
mathematics. More specifically, it is the systematic study of computing systems and
the computations that go behind making the computer function. Computer scientists
need to know computing systems and methods; how to design computer programs,
including the use of algorithms, programming languages, and other tools; and how
software and hardware work together. They also need to understand the analysis and
verification of the input and output.What are computer codesand programs?
Mathematics is an important part of computers, because math is used to write com-
puter codes and programs. The codes are the symbolic arrangement of data (or the
instructions) in a computer program, a term often used interchangeably with “soft-
ware.” The code (also called the source code, or just source) is any series of statements
written in some programming language understandable to the user. This source code
within a software program is usually contained in several text files.The program is the sequence of instructions (or computations) that a comput-
er can interpret and execute. In other words, most programs consist of a loadable
set of instructions that will determine how the computer reacts to user input when
the program is running. The connection between codes and programs is often
heard by students studying computer science or working professionals—and even
in action movies and television programs, as in, “I need to add more lines of code
to the program!”APPLICATIONS
How have computers been used to factor large composite numbers?
Computers have often been used to factor large numbers—and not just by number
theorists having some fun. In fact, factoring such numbers has helped to test the
world’s most powerful computer systems, to promote designs of new algorithms, and
in cryptography used by people who need to protect sensitive information on their
computers. For example, in 1978 several computer experts proposed using the recon-
struction of the prime numbers from the product of two large prime numbers as an
encryption technique. This method of encrypting sensitive data soon blossomed, espe-
cially because of the needs of the military and banking industry. The public also
reaped the benefit of this idea as it eventually led to encryption methods such as the
366 public-key encryption for banking and personal pages on the Internet.