Some Typical Assignment Statements

   mark = mark/7 ;
   price = price + tax ;
   price = price * tax + price ;
   bonus = bonus - 7 ;
   total = total * 5 ;
   month = month % 12 + 1 ;

Equivalent Statements Using Arithmetic Operators

   mark /= 7 ;
   price += tax ;
   price *= tax + price ;
   bonus -= 7 ;
   total *= 5 ;
   month %= 12 + 1 ;

Examples Using printf( ) Library Function

   printf("Hello, World \n");
   printf("%d %f %lf",integer,real,long_integer );
   printf(" %c %s ", character, string );
   printf(" %p ", pointer);
   printf(" %o ", octa_notation);
   printf(" %x ",hexa_notation);
   printf(" %u",unsigned_variable);
   printf(" %s is %d years old ",name,age);
   printf(" \t abcdefg \n\t hijklmn \n\t ... ");
   printf(" He got %f \% in his final exam !!!",grade);

VALID STATEMENTS IN C

• Assignment statement, procedure call

   a = b+c;
   count = scanf ("%d", &n);
   scanf ("%d", &n);

( These always end with semicolons )

• Empty statement

   ;

• Compound statement
  

{ 
   statement 
   {
      statement temp = x ;
      x = y ;
      y = temp ;
   }
   statement 
} 

LOGICAL EXPRESSIONS IN C

• No special equivalent of LOGICAL
• Use char for logical values
• Use 0 for false, non-zero for true
• if ( exp ) then... executes " then " part if ( exp ) is non-zero
• Logical ops return 1 if comparison or combination is true

C	FORTRAN 90	FORTRAN 77	Function
0	.FALSE.	.FALSE.	false
non-zero	.TRUE.	.TRUE.	true
!	!	.NOT.	logical negate
<	<	.LT.	less than
<=	<=	.LE.	less than or equal
>	>	.GT.	greater than
>=	>=	.GE.	greater than or equal
==	==	.EQ.	equal
!=	/=	.NE.	not equal
&&	&&	.AND.	logical AND
||	||	.OR.	logical OR

• Can't use comparisons on strings -- use strcmp :

Example :

strcmp("b", "a") returns {1} (true because b > a)

strcmp("b", "b") returns {0} (false because b cannot be 
                                                  big & small at the same time)

General Form of if ... else Statement

   if ( expression )
       statement_1 ;
   else
       statement_2;

General Form of if statement ( without else statement )

   if ( expression ) statement ;

or ( with more than one statement )

if ( expression )
{
   statement_1;
   statement_2;
   .
   .
   .
   statement_n;
}

Examples of Nested if Statements

Example #1 :

   if ( grade >= 85 )
      if ( final > 90 )
         printf( "Outstanding student !");
      else 
         printf( "Excellent work !" );

Example #2 :

if( cost > sales )
   if( cost/2 > 100*sales )
      printf( "You are in big trouble !!!");
   else
      printf( "You seem to be in trouble. ");

Example #3 :

if( house_value > 500000 )
   if( number_cars > 3 )
      printf( "You are running into debt !!!"); 
   else
      printf( "You are rich." );

Example #4 :

if( house_value > 500000 ) {
   if( number_cars > 3 )
   printf( "You are running into debt !!!"); } 
else
printf( "Buy new cars !!!" );

General Form of if...else if...else Statements

if (expression_1)
   statement_1;
else if (expression_2)
   statement_2;
else if (expression_3)
   statement_3;
   .
   .
   .
else if ( expression_n )
   statement_n;
else
   statement_k; 

Example Use of if...else if...else Statement

/* Function to print the letter grade */

void print_letter_grade(float grade)
{
   if ( grade < 50 )
      printf(" F ");
   else if ( grade < 55 )
      printf(" C- ");
   else if ( grade < 60 )
      printf(" C ");
   else if ( grade < 65 )
      printf(" C+ ");
   else if ( grade < 70 )
      printf(" B- ");
   else if ( grade < 75 )
      printf(" B ");
   else if ( grade < 80 )
      printf(" B+ ");
   else if ( grade < 85 )
      printf(" A- ");
   else 
      printf(" A ");
} 

Operator	Explanation
&	bitwise logical AND
|	bitwise logical OR
^	bitwise exclusive OR
<<	left shift
>>	right shift
~	one's complement

Full set of C operators in order of decreasing precedence

Operator	Associativity
( ) [ ] ->	left to right
! + - ++ -- * & (cast type) sizeof	right to left
* / %	left to right
+ -	left to right
<< >>	left to right
< <= > >=	left to right
= = !=	left to right
&	left to right
^	left to right
|	left to right
&&	left to right
||	left to right
?:	right to left
= += -= *= /= %= &= ^= |= <<= >>=	right to left
,	left to right

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