Cprogramming-c-operators

C-演算子

演算子は、特定の数学関数または論理関数を実行するようコンパイラーに指示する記号です。 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

この章では、各演算子の動作方法について説明します。

算術演算子

次の表は、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：/cprogramming/c_arithmetic_operators [例を表示]

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

関係演算子

次の表は、C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：/cprogramming/c_relational_operators [例を表示]

Operator	Description	Example
==	Checks if the values of two operands are equal or not. If yes, then the condition becomes true.	(A == B) is not true.
!=	Checks if the values of two operands are equal or not. If the values are not equal, then the 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 the 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 the 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 the 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 the condition becomes true.	(A ⇐ B) is true.

論理演算子

次の表は、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：/cprogramming/c_logical_operators [例を表示]

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

ビット演算子

ビット演算子はビットに対して機能し、ビットごとの操作を実行します。 ＆、|、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

バイナリ形式でA = 60とB = 13と仮定すると、それら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

次の表に、Cでサポートされているビットごとの演算子を示します。 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：/cprogramming/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) = 12, i.e., 0000 1100 || |Binary OR Operator copies a bit if it exists in either operand. |(A | B) = 61, i.e., 0011 1101 |^ |Binary XOR Operator copies the bit if it is set in one operand but not both. |(A ^ B) = 49, i.e., 0011 0001 |~ |Binary One's Complement Operator is unary and has the effect of 'flipping' bits. |(~A ) = ~(60), i.e,. -0111101 |<< |Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand. |A << 2 = 240 i.e., 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 = 15 i.e., 0000 1111
|===

=== 割り当て演算子

次の表は、C言語でサポートされている割り当て演算子を示しています-

リンク：/cprogramming/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 the value of A + B to C |+= |Add AND assignment operator. It adds the right operand to the left operand and assign the result to the left operand. |C += A is equivalent to C = C + A |-= |Subtract AND assignment operator. It subtracts the right operand from the left operand and assigns the result to the left operand. |C -= A is equivalent to C = C - A |*= |Multiply AND assignment operator. It multiplies the right operand with the left operand and assigns the result to the left operand. |C *= A is equivalent to C = C * A |/= |Divide AND assignment operator. It divides the left operand with the right operand and assigns the result to the 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 the 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

上記で説明した演算子の他に、 *sizeof* や*？を含む他の重要な演算子がいくつかあります。 ：* C言語でサポートされています。

リンク：/cprogramming/c_sizeof_operator [例を表示]

[cols=",,",options="header",]
|===
|Operator |Description |Example |sizeof() |Returns the size of a variable. |sizeof(a), where a is integer, will return 4. |& |Returns the address of a variable. |&a; returns the actual address of the variable. |* |Pointer to a variable. |*a; |? : |Conditional Expression. |If Condition is true ? then value X : otherwise value Y
|===

=== 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、式の評価方法を決定します。 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くなります。

たとえば、x = 7 + 3 * 2;ここでは、演算子*の優先順位が+より高いため、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、次に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。

リンク：/cprogramming/c_operators_precedence [例を表示]

[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 AND |& |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
|===