Objective-c-operators

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Objective-Cオペレーター

演算子は、特定の数学的または論理的な操作を実行するようコンパイラーに指示する記号です。 Objective-C言語は組み込みの演算子が豊富であり、次の種類の演算子を提供します-

  • 算術演算子
  • 関係演算子
  • 論理演算子
  • ビット演算子
  • 割り当て演算子
  • その他の演算子

このチュートリアルでは、算術演算、リレーショナル演算、論理演算、ビット単位の代入、およびその他の演算子を1つずつ説明します。

算術演算子

次の表は、Objective-C言語でサポートされているすべての算術演算子を示しています。 変数 A が10を保持し、変数 B が20を保持すると仮定します-

リンク：/objective_c/objective_c_arithmetic_operators [例を表示]

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

関係演算子

次の表は、Objective-C言語でサポートされているすべての関係演算子を示しています。 変数 A が10を保持し、変数 B が20を保持すると仮定します-

リンク：/objective_c/objective_c_relational_operators [例を表示]

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.

論理演算子

次の表は、Objective-C言語でサポートされているすべての論理演算子を示しています。 変数 A が1を保持し、変数 B が0を保持すると仮定します-

リンク：/objective_c/objective_c_logical_operators [例を表示]

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.

ビット演算子

ビットごとの演算子はビットに対して機能し、ビットごとの演算を実行します。 ＆、|、および^の真理値表は次のとおりです-

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

A = 60であると仮定します。およびB = 13;今バイナリ形式では、次のようになります-

A = 0011 1100

B = 0000 1101 

A＆B = 0000 1100

A | B = 0011 1101

A ^ B = 0011 0001

〜A = 1100 0011

Objective-C言語でサポートされているビット単位の演算子を次の表にリストします。 変数Aが60を保持し、変数Bが13を保持すると仮定します-

リンク：/objective_c/objective_c_bitwise_operators [例を表示]

[cols=",,",options="header",]
|===
|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
|===

=== 割り当て演算子

Objective-C言語でサポートされている次の代入演算子があります-

リンク：/objective_c/objective_c_assignment_operators [例を表示]

[cols=",,",options="header",]
|===
|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
|===

=== その他の演算子＆map; sizeof＆ternary

 *sizeof* や*？など、他の重要な演算子はほとんどありません。 ：* Objective-C言語でサポートされています。

リンク：/objective_c/objective_c_sizeof_operator [例を表示]

[cols=",,",options="header",]
|===
|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
|===

=== Objective-Cでの演算子の優先順位

演算子の優先順位は、式内の用語のグループ化を決定します。 これは、式の評価方法に影響します。 特定の演算子は、他の演算子よりも優先順位が高くなっています。たとえば、乗算演算子は加算演算子よりも優先順位が高い-

たとえば、x = 7 + 3 * 2;ここでは、演算子*の優先順位が+よりも高いため、xには20ではなく13が割り当てられます。したがって、最初に3 * 2で乗算され、7に加算されます。

ここでは、優先順位が最も高い演算子が表の上部に表示され、優先順位が最も低い演算子が下部に表示されます。 式内では、優先順位の高い演算子が最初に評価されます。

[cols=",,",options="header",]
|===
|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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