Objective C Operators - Objective C

What are Objective-C Operators?

A compiler performs specific mathematical or logical manipulations. The following types of operators are provided by Objective C:

  • Arithmetic Operators
  • Relational Operators
  • Logical Operators
  • Bitwise Operators
  • Assignment Operators
  • Misc Operators

Arithmetic Operator

Some of the arithmetic operators that supported by Objective are shown in the given table. Assume variable A holds 10 and variable B holds 20, then:

Examples

Operator Description Example
+ Adds two operands A + B will give 30
- Subtracts second operand from the first A - B will give -10
* Multiplies both operands A * B will give 200
/ Divides numerator by denominator B / A will give 2
% Modulus Operator and remainder of after an integer division B % A will give 0
++ Increment operator increases integer value by one A++ will give 11
-- Decrement operator decreases integer value by one A-- will give 9

Relational Operators

Relational operators that supported by Objective C are shown in the given table. Assume variable A holds 10 and variable B holds 20, then:

Examples

Operator Description Example
== Checks if the values of two operands are equal or not; if yes, then condition becomes true. (A == B) is not true.
!= Checks if the values of two operands are equal or not; if values are not equal, then condition becomes true. (A != B) is true.
> Checks if the value of left operand is greater than the value of right operand; if yes, then condition becomes true. (A > B) is not true.
< Checks if the value of left operand is less than the value of right operand; if yes, then condition becomes true. (A < B) is true.
>= Checks if the value of left operand is greater than or equal to the value of right operand; if yes, then condition becomes true. (A >= B) is not true.
<= Checks if the value of left operand is less than or equal to the value of right operand; if yes, then condition becomes true. (A <= B) is true.

Logical Operators

Logical operators supported by Objective C language are listed in the below table. Assume variable A holds 1 and variable B holds 0, then:

Examples

Operator Description Example
&& Called Logical AND operator. If both the operands are non zero then condition becomes true. (A && B) is false.
|| Called Logical OR Operator. If any of the two operands is non zero then condition becomes true. (A || B) is true.
! Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true, then Logical NOT operator will make false. !(A && B) is true.

Bitwise Operators

Bitwise operator performs bit by bit operations. The truth tables for &, |, and ^ are as follows:Example

p q p & q p | q p ^ q
0 0 0 0 0
0 1 0 1 1
1 1 1 1 0
1 0 0 1 1

Assume if A = 60; and B = 13; They are represented in binary format as follows:


A = 0011 1100
B = 0000 1101
-----------------
A&B = 0000 1100
A|B = 0011 1101
A^B = 0011 0001
~A = 1100 0011

The Bitwise operators supported by Objective-C are listed in the below table. Assume variable A holds 60 and variable B holds 13 then:

Operator Description Example
& Binary AND Operator copies a bit to the result if it exists in both operands. (A & B) will give 12, which is 0000 1100
| Binary OR Operator copies a bit if it exists in either operand. (A | B) will give 61, which is 0011 1101
^ Binary XOR Operator copies the bit if it is set in one operand but not both. (A ^ B) will give 49, which is 0011 0001
~ Binary Ones Complement Operator is unary and has the effect of 'flipping' bits. (~A ) will give -61, which is 1100 0011 in 2's complement form.
<< Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand. A << 2 will give 240, which is 1111 0000
>> Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand. A >> 2 will give 15, which is 0000 1111

Assignment Operators

Assignment operators supported by Objective C are listed below:

Examples

Operator Description Example
= Simple assignment operator, Assigns values from right side operands to left side operand C = A + B will assign value of A + B into C
+= Add AND assignment operator, It adds right operand to the left operand and assigns the result to left operand C += A is equivalent to C = C + A
-= Subtract AND assignment operator, It subtracts right operand from the left operand and assigns the result to left operand C -= A is equivalent to C = C - A
*= Multiply AND assignment operator, It multiplies right operand with the left operand and assigns the result to left operand C *= A is equivalent to C = C * A
/= Divide AND assignment operator, It divides left operand with the right operand and assigns the result to left operand C /= A is equivalent to C = C / A
%= Modulus AND assignment operator, It takes modulus using two operands and assigns the result to left operand C %= A is equivalent to C = C % A
<<= Left shift AND assignment operator C <<= 2 is same as C = C << 2
>>= Right shift AND assignment operator C >>= 2 is same as C = C >> 2
&= Bitwise AND assignment operator C &= 2 is same as C = C & 2
^= bitwise exclusive OR and assignment operator C ^= 2 is same as C = C ^ 2
|= bitwise inclusive OR and assignment operator C |= 2 is same as C = C | 2

Misc Operators ? sizeof & ternary

Some of the other operators including sizeof and ? : supported by Objective-C Language.

Examples

Operator Description Example
sizeof() Returns the size of an variable. sizeof(a), where a is integer, will return 4.
& Returns the address of an variable. &a; will give actual address of the variable.
* Pointer to a variable. *a; will pointer to a variable.
? : Conditional Expression If Condition is true ? Then value X : Otherwise value Y

Operators Precedence in Objective-C

Grouping of terms in an expression is determined by operator precedence. The operators have higher precedence than others depends on how the expression I is evaluated.

For example, x = 7 + 3 * 2; here, x is assigned 13, not 20 because operator * has higher precedence than +, so it first gets multiplied with 3*2 and then adds into 7.

The operators with the highest precedence appear at the top of the table; those with the lowest appear at the bottom. Within an expression.The higher precedence operators will be evaluated first.

Examples

Category Operator Associativity
Postfix () [] -> . ++ - - Left to right
Unary + - ! ~ ++ - - (type)* & sizeof Right to left
Multiplicative * / % Left to right
Additive + - Left to right
Shift << >> Left to right
Relational < <= > >= Left to right
Equality == != Left to right
Bitwise XOR ^ Left to right
Bitwise OR | Left to right
Logical AND && Left to right
Logical OR || Left to right
Conditional ?: Right to left
Assignment = += -= *= /= %=>>= <<= &= ^= |= Right to left
Comma , Left to right

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