freeCodeCamp/guide/english/c/operators/index.md

title

title
Operators

Operators in C

1. Arithmetic Operators

• + Adds to operands (values)

  int a = 6;
  int c = a + 1; // c = 7
  

• -Subtracts the second operand from the first

  int a = 8;
  int b = 9;
  int c = a - b; // c = -1
  

• * Multiplies two operands

  int a = 8;
  int b = 9;
  int c = a * b; // c = 72
  

• / Divides the first operand by the second

  int a = 8;
  int b = 4;
  int c = a / b; // c = 2
  

• % Gives the remainder after an integer division

  int a = 8;
  int b = 9;
  int c = b % a; // c = 1 because b = 1*a + 1 = 8 + 1
  

• ++ Increases int value by one

  int a = 8;
  a++; // a = 9
  int b = a++; // postfix operator; a = 10, b = 9
  int c = ++a; // prefix operator; a = 11, c = 11
  

• -- Decreases int value by one

  int a = 8;
  a--; // a = 7
  int b = a--; // postfix operator; a = 6, b = 7
  int c = --a; // prefix operator; a = 5, c = 5
  

// C Program to demonstrate the working of arithmetic operators #include <stdio.h> int main() { int a = 9,b = 4, c;

c = a+b;
printf("a+b = %d \n",c);

c = a-b;
printf("a-b = %d \n",c);

c = a*b;
printf("a*b = %d \n",c);

c=a/b;
printf("a/b = %d \n",c);

c=a%b;
printf("Remainder when a divided by b = %d \n",c);

return 0;

}

2. Relational Operators

• == Equal - true when the two operands are equal

  int a = 5, b = 5;
  bool c = (a == b); // c = true
  

• != Not equal - true when the two operands are NOT equal

  int a = 5, b = 6;
  bool c = (a != b); // c = true
  

• > Greater than - True when first operand is bigger than the second.

  int a = 8, b = 5;
  bool c = (a > b); // c = true
  

• < Less than - True when the first operand is smaller then the second.

  int a = 5, b = 8;
  bool c = (a < b); // c = true
  

• >= Greater than or equal - True when the first operand is bigger, or equal to the second.

  int a = 8, b = 5;
  bool c = (a >= b); // c = true
  bool d = (a >= 8); // d = true
  

• <= Less than or equal - True when the first operand is smaller or equal to the second.

  int a = 5, b = 8;
  bool c = (a <= b); // c = true
  

3. Logical Operators

• && AND operator - True when both of the operands are true.

  bool c = (5 < 6) && (8!=7); // both operands true, therefore c = true
  

• || OR operator - True when either the first or the second operands are true (or both)

  bool c = (5 < 6) || (8 == 7) // first operand is true, therefore c = true
  

• ! NOT operator - True when the operand is false.

  bool c = !(8 == 7) // translate: NOT (false), therefore c = true
  

4. Bitwise Operators

• & AND operator - If at a place there is a bit in both operands, then it is copied to the result

  A = 11001
  B = 01000
  RESULT = 01000
  

• | OR operator - If at a place there is a bit in either operands, then it is copied to the result

  A = 11001
  B = 01000
  RESULT = 11001
  

• ^ XOR (exclusive OR) operator - If at a place there is a bit in one of the operands (not both), then it is copied to the result

  A = 11001
  B = 01000
  RESULT = 10001
  

• ~ Negation operator - Reverses the bits. 1 -> 0, 0 -> 1

  C = 01000
  RESULT = 10111
  

• << Left shift operator - The left operand is moved left by as many bits, as the right operand

  A = 11001
     A << 2
  RESULT = 00100
  

• >> Right shift operator - The left operand is moved right by as many bits, as the right operand

  A = 11001
     A >> 2
  RESULT = 00110
  

5. Assignment Operators

• =

  int a = 7; // 'a' is going to be equal to 7
  

• +=

  int a = 7;
  a += 5; // equivalent to a = a + 5 = 7 + 5 = 12
  

• -=

  int a = 7;
  a -= 2; // equivalent to a = a - 2 = 7 - 2 = 5
  

• *=

  int a = 7;
  a *= 3; // equivalent to a = a * 3 = 7 * 3 = 21
  

• /=

  int a = 21;
  a /= 3; // equivalent to a = a / 3 = 21 / 3 = 7
  

• %=

  int a = 21;
  a %= 5; // equivalent to a = a % 5 = 21 % 5 = 1
  

Misc Operators ↦ sizeof & ternary Besides the operators discussed above, there are a few other important operators including sizeof and ? : supported by the C Language.

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

6. Operator precedence in C

Operators with the highest precedence appear at the top of the list. Within an expression, operators with higher precedence will be evaluated first.

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