BASICS OF C

• Questions
• Header Files
• Data Types
• Rules for constructing variable and character constant
• Delimiters
• Operators
• Decision Statement

      QUESTIONS:-

• Write a program to find sum of 2 numbers.
• Write a program to find difference of 2 numbers.
• Write a program to find sum, difference, product, division, mod of two numbers. 
• Write a program to find Simple Interest.
• Write a program to find perimeter and area of a rectangle.
• Write a program to find circumference and area of a circle.
• Write a program to find average of 3 numbers.
• Write a program to calculate sum of 5 subjects and print percentage.
• Write a program to swap two numbers.
• Write a program to swap two numbers without using third variable.
• Write a program to print square of a given number.
• Write a program to print size occupied by different data types.

•  HEADER FILES:- In C, header files contain the set of predefined standard library functions. The "#include"                      preprocessing directive is used to include  the header files with ".h" extension in the program.

• • stdio.h :- Input/Output function
  • conio.h :- Console Input/Output functions
  • stdlib.h:- General utility functions
  • math.h :- Mathematical functions
  • string.h :- String functions
  • time.h :- Date and time functions
  • limits.h :- size of basic types
  
  

• DATA TYPES:-

• RULES FOR CONSTRUCTING VARIABLE AND CHARACTER CONSTANT:-

Rules for constructing CHARACTER CONSTANT:-

• A character constant is a single alphabet, a single digit or a single special symbol enclosed within single inverted commas. Both the inverted commas should point to the left. 
• The maximum length of a character constant can be 1 character. Ex: 'A' , 'I' , '5' , '='.

Rules for constructing VARIABLE NAMES:-

      In C language, any user defined variable name is called identifier. This may be variable names, function names, goto label name, any other data type like structure, union,enum names or typedef name.

• A variable name is any combination of 1 to 31 alphabets, digits or underscores. Some compilers allow variable names up to 247 characters. 
• The first character in the variable name must be an alphabet or underscore.
• No special symbol other than an underscore (as in gross_sal) can be used in a variable name. Ex:- rate, time, si_int, m_hra, bas_sal, etc.
• Keywords should not be used as variable names because  if we do so, we are trying to assign a new meaning to the keyword, which is not allowed by the computer.
  

• DELIMITERS:-     
  
•  :    Colon  :- Useful for label
•  ;    Semicolon :- Terminates the statement
•  ( )  Parentheses :- Used in expression and function
•  [ ]  Square Bracket :- Used for array declaration
•  { }  Curly Brace :- Scope of the statement
•   #   Hash :- Preprocessor directive
•    ,   Comma :- Variable separator

• OPERATORS:-

• Arithmetic Operator:- +,-,*,/,%
• Unary Operator:- ++,--,&
• Relational Operator:- >,<,>=,<=,==,!=
• Logical Operator:- &&,||,!
• Assignment Operator:- =
• Conditional Operator:- ?:
• Bitwise Operator:- >>,<<,&,|,^,~

• DECISION STATEMENT:-

• If-else statement
• Nested if-else statement 
• Break Statement
• Continue Statement
• Goto Statement
• Switch() statement
• Nested switch() case
• Switch case() and Nested if