INTRODUCTION TO C++
C++ IS A GENERAL PURPOSE PROGRAMMING LANGUAGE INVENTED IN EARLY 1980S BY BJARNE STROUSTRUP. IT INCLUDES MODERN PROGRAMMING TECHNIQUES SUCH AS Object Oriented PROGRAMMING(OOP).
1. OBJECT ORIENTED
2. MODULAR PROGRAMMING
3. PORTABILITY
4. SPEED
1.TOKENS
A TOKEN IS THE SMALLEST MEANINGFUL COMPONENT. YOU CAN BREAK A C++ PROGRAM INTO TOKENS. ALL THE TOKENS OF A PROGRAM ARE TOGETHER KNOWN AS TOKEN SET.
2. KEYWORDS
KEYWORDS ARE REVERSED WORDS AND CANNOT BE USED BY THE PROGRAMMER FOR VARIABLE OR METHOD NAMES. SOME OF THE C++ KEYWORDS ARE ; INT,CHAR,VOID,FOR,DO,IF,SWITCH, ETC.
3. VARIABLE
A VARIABLE IS A NAMED LOCATION IN MEMORY THAT STORES A VALUE. VARIABLE ARE USED IN C++ TO CONTAIN DATA. THEY MAY CHANGE THEIR VALUES DURING EXECUTION OF THE PROGRAM.
FOR EXAMPLE,INT SUM; IT SHOWS THAT NUM IN AS AN INT VARIABLE.3
4. IDENTIFIERS
IDENTIFIERS ARE THE NAMES OF VARIABLES , METHODS,CLASSES, PACKAGES AND INTERFACES. THEY REPRESENT NAME OF THE DIFFERENT COMPONENTS OF A C++ PROGRAM.
THE NAME OF THE IDENTIFIERS CAN ONLY BEGIN WITH AN ALPHABET, THE UNDERSCORE OR A DOLLAR SIGN , FOR EXAMPLE, HELLO,$MONEY,_TWOTHIRDS, MYNUMBER.
5.OPERATORS
AN OPERATOR IN C++ IS A SYMBOL THAT PERFORMS CERTAIN OPERATIONS ON ONE OR MORE OPERANDS TO PRODUCE AN RESULT.
INT AVERAGE;// IT SHOWS THAT THE AVERAGE IS A VARIABLE THAT STORES VALUE OF INT TYPE.
FLOAT PERCENTAGE;// IT SHOWS THAT PERCENTAGE IS A VARIABLE THAT STORES DECIMAL VALUES.
CHAR GRADE;// IT SHOWS THAT GRADE IS A VARIABLE THAT STORES CHARACTER VALUE.
C++ IS A GENERAL PURPOSE PROGRAMMING LANGUAGE INVENTED IN EARLY 1980S BY BJARNE STROUSTRUP. IT INCLUDES MODERN PROGRAMMING TECHNIQUES SUCH AS Object Oriented PROGRAMMING(OOP).
CHARACTERISTICS OF C++
SOME OF THE FEATURES OF C++ ARE AS FOLLOWS1. OBJECT ORIENTED
2. MODULAR PROGRAMMING
3. PORTABILITY
4. SPEED
BASIC ELEMENTS OF C++
BEFORE YOU LEARN TO WRITE C++ PROGRAMS, YOU SHOULD KNOW SOME BASIC ELEMENTS OF C++ PROGRAMS.1.TOKENS
A TOKEN IS THE SMALLEST MEANINGFUL COMPONENT. YOU CAN BREAK A C++ PROGRAM INTO TOKENS. ALL THE TOKENS OF A PROGRAM ARE TOGETHER KNOWN AS TOKEN SET.
2. KEYWORDS
KEYWORDS ARE REVERSED WORDS AND CANNOT BE USED BY THE PROGRAMMER FOR VARIABLE OR METHOD NAMES. SOME OF THE C++ KEYWORDS ARE ; INT,CHAR,VOID,FOR,DO,IF,SWITCH, ETC.
3. VARIABLE
A VARIABLE IS A NAMED LOCATION IN MEMORY THAT STORES A VALUE. VARIABLE ARE USED IN C++ TO CONTAIN DATA. THEY MAY CHANGE THEIR VALUES DURING EXECUTION OF THE PROGRAM.
FOR EXAMPLE,INT SUM; IT SHOWS THAT NUM IN AS AN INT VARIABLE.3
4. IDENTIFIERS
IDENTIFIERS ARE THE NAMES OF VARIABLES , METHODS,CLASSES, PACKAGES AND INTERFACES. THEY REPRESENT NAME OF THE DIFFERENT COMPONENTS OF A C++ PROGRAM.
THE NAME OF THE IDENTIFIERS CAN ONLY BEGIN WITH AN ALPHABET, THE UNDERSCORE OR A DOLLAR SIGN , FOR EXAMPLE, HELLO,$MONEY,_TWOTHIRDS, MYNUMBER.
5.OPERATORS
AN OPERATOR IN C++ IS A SYMBOL THAT PERFORMS CERTAIN OPERATIONS ON ONE OR MORE OPERANDS TO PRODUCE AN RESULT.
VARIABLE DECLARATION
BEFORE USING VARIABLE YOU HAVE TO DECLARE THE VARIABLE'S NAME AND TYPE.INT AVERAGE;// IT SHOWS THAT THE AVERAGE IS A VARIABLE THAT STORES VALUE OF INT TYPE.
FLOAT PERCENTAGE;// IT SHOWS THAT PERCENTAGE IS A VARIABLE THAT STORES DECIMAL VALUES.
CHAR GRADE;// IT SHOWS THAT GRADE IS A VARIABLE THAT STORES CHARACTER VALUE.
STRUCTURE OF C++ PROGRAMS// FIRST PROGRAM
THIS IS A COMMENT LINE. ALL LINES BEGINNING WITH THE TWO SLASH SIGNS (//) ARE CONSIDERED COMMENTS. THESE ARE NOT PARTS OF THE ACTUAL PROGRAMS.#INCLUDE<IOSTREAM.H>
LINES BEGINNING WITH A HASH SIGN ARE DIRECTIVES FOR THE PREPROCESSOR. THEY ARE INDICATIONS FOR THE COMPILER'S PREPROCESSOR. IN THIS CASE, THE DIRECTIVE #INCLUDE IOSTREAM TELLS THE THE PREPROCESSOR TO INCLUDE THE IOSTREAM STANDARD FILE.VOID MAIN ( )
THIS IS THE BEGINNING OF THE DEFINITION OF THE Main Function. THE MAIN FUNCTION IS THE POINT BY WHERE ALL C++ PROGRAMS START THERE EXECUTION.
THE WORD MAIN IS FOLLOWED BY A PAIR OF PARENTHESES ( ). NEXT TO THE PARENTHESES, THE BODY OF THE MAIN FUNCTION IS ENCLOSED IN BRACES{ }. THE CODE WITHIN THESE BRACES IS WHAT THE FUNCTION DOES WHEN IT IS EXECUTED.
COUT<<"HELLO MY TRICKY UNIVERSE";
THIS LINE IS THE IS A C++ STATEMENT, COUT IS THE NAME OF THE STANDARD OUTPUT STREAM IN C++, AND THE MEANING OF THE ENTIRE STATEMENT IS TO PRINT A SEQUENCE OF CHARACTER( IN THIS CASE, HELLO MY TRICKY UNIVERSE) ON THE MONITOR. THE STATEMENT ENDS WITH A SEMICOLON CHARACTER(;)
EXAMPLE
// A PROGRAM BY HTTP://MYTRICKYUNIVERSE.BLOGSPOT.IN
#INCLUDE<IOSTREAM.H>
VOID MAIN ()
{
COUT<<"HELLO MTU";
}
