Session 2 Keyword Operator

Constants

Integer Constants (int)     5 62 64 0 -78 45 -46  +ve number, -ve number , Zero
Real Constant    (float)      3.75 8.54 -5.3 -0.2
Character constant   (char)  '5'  'a'  'V'  '4'   '+' '*' '9'

Pi = 22/7=  3.14285714286..........  ---> floating Value


3.56    float   Crt
'a'     char    crt
176     int      Crt
'125'   char    Error       ' '=> Length within single quotes is 1
'name' char    Error
'95.5'  char    Error
 a      int     Error
mukesh  int     Error
.954    float   Crt


'ad'   error
34.3   float
Me     Error
'0'    Char
'10.2' Error


Normal Language                             C Language
Alphabets                                   Keywords-> int(integer) char(character) float(floating value)
Words Meaning                               Operators -> + - * /  [45->Operators]
Sentence   [Full stop]                      Seperators  ->  ; : {} ()
Grammar --> Rules & Regulations             Syntax-> format, Error


What is a Keywords ?
Keywords are Reserved or a predefined words it has a special Meaning. int(integer) char(character) float(floating)
Ex: int  --->  it represents Positive, Negative number and Zero
char  --> Character constants with ' ' Single quotes, with a length Only one
Valid   'a'  'B'  '2'  '+'
Invalid   'hello' '123' '1.2'

Variables

Maths
4x+2y=0  -> Equation
4x+2y    -> Expression
4 -> Constant
2 -> Constant
x -> Variable
y -> Variable
+ -> Addition(Operation), Plus(Symbol)
= -> is Equal to (Symbol) , Assignment(Operator)


Assignment Operator (=)
Conditions
1. It requires 2 argument  Ex:    a = 5
2. Left Side Argument must be variable.  Ex: a =  6
3. Right Side Argument might be Variable (a=b), constant(a=5), Expression(a=5*2)
4. Left Side Argument is called L-Value   a=12   a-> L-Value  Error: lvalue required

a=7   Invalid  semi colon (;) is must
a=5;  Valid

a=2;     a-> 2  b->3  c-> 6
b=3;
c=2+4;

a = ;  Error Expression syntax error
  = b; Error

Assignment      Left Arg =  Right Arg

a=5;        a-> 5  7
b=7;		b-> 7  8
c=8;		c-> 8  9
d=9;		d-> 9  7
a=b;
b=c;
c=d;
d=a;

a=5;       a-> 5   4
b=-4;	   b-> -4  9
c=9;       c-> 9     +9 -9   -9=-9;
a=-b;
b=c;
-c=-b;
-a=-b; -4=-9          -5=x-y
   In L-value,  Any variable with (-) changes into a expression .  Expression gives a constant

Priority

a=2+3;  5
+
=

a=2+3+5; 10  If Priorities same, (+) it starts from Left to right
a=5+5;

a=7-5+2; ->2+2;-> 4;
a=5+2-7; ->7-7; 0;
 + -
  =

a=2+3*5;   1.*  2.+  3.=
a=2+15;  17
a=2*3+3*4;
a=6+3*4;
a=6+12;
a=18;

a=(2+3)*5;
a=5*5;
a=5*(3-1)+(3-1); 5*2+2; 10+2; 12;
First Priority goes to the operator inside the ().
() Changes the default priority.

a=3*10/2;    * / (same priority) Left to Right
a=10/5/2;


Maths 				C Lang
+  Add Sum           +   Sum
-  Sub Dif           -
X  Mul product       *
/  Div Quotient      /
	   Remainder     %

  (/)  Quotient - Result
int/int     => int
int/float   => float
float/float => float
float/int   => float

a=5/2; 2
a=-5/2; -2
a= 5/-2; -2
a=-5/-2; 2
a= 5.0/2; 2.5
a=5/2.0;  2.5
a=5.0/2.0; 2.5
a=2/5;  0
a= 2/5.0; 0.4
a=2.0/5; 0.4