Unit-2 (Operators) ANAND KR.SRIVASTAVA

Transcription

1 Unit-2 (Operators) ANAND KR.SRIVASTAVA 1

2 Operators in C ( use of operators in C ) Operators are the symbol, to perform some operation ( calculation, manipulation). Set of Operations are used in completion of any task. C is the Programming language to perform some task. & & 2

3 Operands & Operators Any operation is a combination of two things: 1. Operands 2.Operator Operators works on operands. Operands may be A Data Value A Data Variable A Expression Examples: , a - 3, b + c, (a+b)+(b+10) Here, 10,4,3 are Data values and a,b,c are variables. 3

4 Types of Operators On the basis of number of operands, operators are divided into three types:- Unary Operators Acts upon one operand Binary Operators Acts upon two operands Ternary Operators Acts upon three operands. 4

5 Types of Operators:- ( On the basis of features of operators) Increment or Decrement Operator ( Unary) Arithmetic Operators Relational Operators Logical Operators Binary Assignment Operators Bitwise Operators Conditional Operators ( Ternary) Special Operators 5

6 Arithmetic Operators Operator Symbol Action Example Addition + Adds operands x + y Subtraction - Subs second from first x - y Negation - Negates operand -x Multiplication * Multiplies operandsx * y Division / Divides first by second x / y (integer quotient) Modulus % Remainder of divide op x % y 6

7 Relational Operators (Relational comparison ) Comparisons can be done with the help of relational operators These consist of:- Operator Meaning < less than <= less than equal to > greater than >= greater than equal to = = Equal to!= Not equal to 7

8 Logical Operators ( Logical comparison ) Expression which combines two or more relational expression is termed as a logical or compound relational expression The result of these operators is either TRUE or FALSE. Logical expressions are:- && logical AND Logical OR! Logical NOT Ex- if (age>55 && salary <1000) 8

9 Assignment Operator Used to assign the result of an expression to a variable. ex- int i=20; 1. Simple Assignment e.g. = 2. Compound Assignment e.g. +=, -=, *=, /=, &= 3. Expression Assignment e.g. a=5+(b=8 + (c=2)) - 4 9

10 Operators continued.. x + = y+1; is same as x = x + (y+1) i.e. += means add y+1 to x Similarly.. a=a-1 a - = 1; a=a*(n+1) a *= n+1; a=a/(n+1) a/= n+1; Q: int z=10; z += 34; z *= 2 ; z -=5; z += z+1; 10

11 Increment and Decrement C has two very useful operators not generally found in other languages. These are the increment and decrement operators. i.e ++ and operator adds 1 to the operand and -- operator subtracts 1 to the operand. Both these operators are unary operators and take the following form. ++m (prefix operator) ; or m++ (postfix operator); --m; or m--; ++m & m++ means m = m+1; -- m & m-- means m = m-1; 11

12 Ex int m = 5, y ; y = ++m ; printf ( %d%d " y,m ); Result??? int m = 5, y ; y = m++ ; printf ( %d%d " y,m ); Result????? 12

13 Conditional Operator.. A ternary operator pair?: is available in C to construct conditional expressions of the form. exp1? exp2 : exp3; Operator?: works as follows: exp1 is evaluated first. If it is nonzero (true),then the expression exp2 is evaluated and becomes the value of the expression otherwise vice versa. 13

14 Example. a=10 ; b=15; x=(a>b)? a : b; It can be written as if ( a > b ) x = a; else x=b; 14

15 Bitwise Operator. C has distinction of supporting special operators known as Bitwise Operators for manipulation of data at bit level. These are used to test bits. Operators & Meaning bitwise AND bitwise OR ^ << shift left >> shift right bitwise exclusive OR (Ex-OR) ~ One s complement 15

16 Bitwise Operator. Examples - int a = 4, b = 3 a = b = a & b = a b = a ^ b = In Ex-OR (if both bits are same : 0) (if both bits are diff : 1) a = 10 b = ~ a => ~ (1010) =>

17 B Bitwise operators The shift operator: x << n Shifts the bits in x n positions to the left, shifting in zeros on the right. If x = x >> n x << 1 equals Shifts the bits in x n positions right. shifts in 0 if it is an unsigned integer x >> 1 is (unsigned) 17

18 Operator Precedence( priority) Parenthesis Unary operator ( ~, ++,--,-) Arithmetic ( first - /,%,* then +,-) Shift Left & Right Comparison ( first- >,>=,<,<= then ==,!=) Bitwise AND OR NOT Logical AND OR Conditional Operator Assignment D E C R E A S I N G O R D E R 18

19 Operator Precedence Operator Precedence Associativity ( ) 1 L to R ~, ++, --, unary - 2 R to L *, /, % 3 L to R +, - 4 L to R <<, >> 5 L to R <, <=, >, >= 6 L to R ==,!= 7 L to R & 8 L to R ^ 9 L to R! 10 L to R && 11 L to R 12 L to R? : 13 R to L =, +=, -=, etc. 14 R to L 19

20 Special Operators comma(,) {Left to Right} Sizeof(parameter) { show the size of given parameter) Address operator(&) Pointer operator(* ) Member selection operator(. And ->) Q: int z= ( a=3, b = 2, c=4, a+b+c); 20

21 Problems Q1. a = 2 * 3 % / (-2) + 5 / 8 Q2. kk = 3 / 2 * 4 % / Q3. int i = 4, j = -1, k = 0, y, z ; y = i + 5 && j + 1 k + 2 ; z = i + 5 j + 1 && k + 2 ; printf ( "\ny = %d z = %d", y, z ) ; 21

22 Problems Q4. int i = 4, j = -1, k = 0, w, x, y, z ; w = i j k ; x = i && j && k ; y = i j && k ; z = i && j k ; printf ( "\nw = %d x = %d y = %d z = %d", w, x, y, z ) ; Q5. int z, x = 5, y = - 10, a = 4, b = 2 z = x y * b / a 22

23 Problems Q6. int a = 10, b b = a a; Print a, b Q7. int a = 4; printf( %d%d, a a, a++); Q8. int i = 5; printf( %d, i = ++i = = 6); 23

24 Problems Q9. int a = 3, b b = ++a + ++ a + ++a; Print a, b Q10. int a = 4, b ; b = a++ + a++ + a++; Print a, b Q11. int i = 5, j ; j = ++i + i i; Print i, j 24

25 Problems Q12. Point out the errors, if any (a) int * 150; (b) name = Ajay ; (c) Varchar = 3 ; (d) 3.14 * r * r * h = vol_of_cyl ; (e) area = 3.14 * r ** 2; (f) a = b = 3 = 4 ; 25

26 Problems Q13. void main() { float a = 5, b = 2; int c; c = a % b; printf( %d, c); Q14. int c=0,d=5,e=10,a; a=c>1?d>1 e>1?10:20:30; printf( a=%d,a); 26

27 Problems Q15. int x, y, z ; x=y=z=1; z= ++x + ++y + ++z; printf( %d%d%d,x,y,z); Q16. #define x 5+2 void main( ) { int a; a = x * x * x; printf( %d, a); } 27

28 Problems Q17. void main( ) { int a; a=sizeof( 5.6 ); printf("%d",a); } Q18. int a=0,b=10; if(a=0){ printf("true"); } else{ printf("false"); } 28