Introduction to C and C++ Programming
 
Monday, March 6, 1995
11 AM -- 5 PM Eastern Time
 
Dr. H. E. Dunsmore
Department of Computer Science
Purdue University
West Lafayette, Indiana

Copyright 1995, H.E. Dunsmore, Purdue University


 CLASS SCHEDULE 

  11:00-12:00    (1) Introduction to C and C++

  12:00-12:30    BREAK 

  12:30- 1:25    (2) Data Types and Program Structure

   1:25- 1:30    BREAK 

   1:30- 2:30    (3) Standard Operations and Functions

   2:30- 3:00    BREAK 

   3:00- 3:55    (4) If (Decision) Statements

   3:55- 4:00    BREAK 

   4:00- 5:00    (5) Loops



 INTRODUCTION TO C AND C++

  The C and C++ Languages

  Comments

  iostream.h

  Output and Input


 THE C AND C++ LANGUAGES

  Machine language

  String of zeroes and ones

  Understandable and executable by computer

  No translation necessary
 001010110010

  Extremely difficult for human programmer to make sense of
such statements


  Assembly language
 ADD X,Y

  Programming languages
 for (counter = 0; counter <= NUM; ++counter)

  Programming language evolution

  Motivation to produce languages that lead to greater productivity and
reduction in cost of software development


  C and C++ becoming languages of choice for many software developers

  Ease of use and powerful capabilities

  C++ is ``better'' than C

  Name C++ was derived from language name C and ++
(increment) operator indicating that C++ is ``one language better than
C''


  C++ adds extensions that improve language's syntax

  Easier to use

  Support data abstraction and object-oriented programming

  Object-oriented approach helps software developers conceptualize
and build complex software systems while managing software complexity


  C++ is approximate superset of C

  Most of constructs of C are included in C++

  C++ was developed by Bjarne Stroustrup of AT&T

  C++ has been available outside AT&T since approximately 1985

  Several C++ features have been adopted as part of ANSI standard C
language

  Function prototypes, ``void'' type, and const type specifier


 COMMENTS


  Standard C comment format:
 /* This is a typical C comment */

  C++ introduced new format:
 // This is a C++ style comment

  On any line, after // is encountered, everything to end of 
line is comment

 // This program uses function minute_convert to
 // calculate the minutes in a certain number of
 // days and hours
 #include <iostream.h>
 int minute_convert (int, float);
 void main ()
    {
     // Output the number of minutes in
     // 3 days and 6.5 hours
     cout << minute_convert (3, 6.5) << endl;
    }

 // Function to convert days and hours to minutes
 int minute_convert (int days, float hours)
    {
     int days_minutes = days * 24 * 60;
     int part_day = int (hours * 60); // truncates here
     return (days_minutes + part_day);
    }


  Entire lines and right sides of lines (following //) serve as
comments

  C style comment is still useful for commenting large blocks of text:
 /* This is a multi-line comment
    that could go on
    and on 
    forever */


 iostream.h


  iostream.h is standard C++ #include file for input/output

  Most C++ programs begin with the statement
 #include <iostream.h>

  Directs C++ compiler to include code from file iostream.h
while compiling program


 OUTPUT AND INPUT


  Standard output in C++ is accomplished via
 cout << stuff-to-output;

   cout  is object that directs output to standard output 
device (usually screen)

   <<  is output operator

 cout << "Please enter your age";

  To signify end-of-line:
 cout << "Please enter your age" << "  n";
 cout << "Please enter your age" << endl;


   cout  is able to determine variable's type (such as
integer or float) and outputs it appropriately
 cout << "Gino is now age " << how_old << endl;

  If how_old is integer variable with value 30...
 Gino is now age 30


  Printing multiple items on one line:
 cout << "There are ";
 cout << number;
 cout << " people with an average weight of ";
 cout << weight;
 cout << endl;
 There are 30 people with an average weight of 129.5
 cout << "There are " << number << " people with an average weight of ";
 cout << weight << endl;


  Standard input in C++ is accomplished via
 cin >> variable;

   cin  is object that maps to standard input device (usually
keyboard)

   >>  is input operator


  C++ compiler determines variable's type
and inputs and stores value appropriately
 cin >> number;

  Consecutive  cin  statements:
 cin >> number;
 cin >> weight;

  Can also be accomplished via multiple occurrences of input
operator:
 cin >> number >> weight;

 char grade;
 cin >> grade;

  Gets next non-whitespace character 
 char name[30];
 cin >> name;

  Input character string from standard input device and store
it in variable name

  String is terminated by end-of-line or any whitespace


   cerr  object can be used to write to standard error device
and is used much like  cout :
 cerr << error-stuff-to-output << endl;

  Allows error (or informational) messages to be sent to 
console even if standard output device ( cout ) has been
re-directed elsewhere