Download Programming Life Cycle (Compilers)

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Structured programming wikipedia, lookup

C Sharp (programming language) wikipedia, lookup

Program optimization wikipedia, lookup

Name mangling wikipedia, lookup

Compiler wikipedia, lookup

Library (computing) wikipedia, lookup

Cross compiler wikipedia, lookup

Interpreter (computing) wikipedia, lookup

Comment (computer programming) wikipedia, lookup

GNU Compiler Collection wikipedia, lookup

Transcript
Lecture 2
Programming life cycle
computer piano analogy
•
•
•
•
Piano + player - computer hardware
Musical score/notes - software or program
Composer - programmer
A music box is set with one melody – similar
to a microwave's preset computer chip
Algorithm
• An algorithm is a set of steps to accomplish a task
• High level language and source code are
synonyms. Examples include C, C++, Pascal, Java,
COBOL, Fortran, Python …
• All these languages have very specific syntax. This
allows a compiler program to read them and
translate them into machine code.
• Machine code-the final executable file that can
be run as an application.
HLL, pseudocode, syntax
• All High level Languages (HLL) have similar
constructs such as a "while" loop, "if then"
statements and others. Therefore a programmer
often first writes code in Pseudocode.
• Pseudocode- code that almost source code but
cannot be run through a compiler since it does
not have the correct syntax.
• Syntax- the exact proper way a HLL must be
written in for a compiler program to work.
Compiler
• source code
machine code
Compiler
• Source code is stored in a simple text file
• machine code is stored in an executable file or
an application file.
Sample pseudocode 2
Registration system in BC.
• First we will keep all information in two tables (on the
hard disk but copied to RAM when the program runs:
– The first is a students table that has students� addresses,
courses taken or registered for and grades. �
– The second is a course database that has the course
number, hours, number enrolled and enrollment limit.
• Enter all courses that will be offered this semester
• If a new student comes to register enter name into
student database
• For each course a student wants to take
– i. If the course is not full, in the course table increment the
number enrolled and in the student table enter the course
number for that student.
– ii. If the course is full inform the student that they would
need an overtally.
Sample pseudocode 1
average entered grades
• prepare the following three variables (a spot in
memory to store things):
– nstudents- number of grades entered so far, sum-sum
of grades so far, avg-average of grades
• while entered grade from user is still not negative
– nstudents = nstudents+1
– read another grade from user
– add grade to sum
• avg=sum/nstudents
• print avg to the screen