Operators in C

An operator is a symbol that operates on a value or a variable. For example: + is an operator to perform addition.

C has a wide range of operators to perform various operations.

C Arithmetic Operators

An arithmetic operator performs mathematical operations such as addition, subtraction, multiplication, division etc on numerical values (constants and variables).

OperatorMeaning of Operator+addition or unary plus-subtraction or unary minus*multiplication/division%remainder after division (modulo division)Example 1: Arithmetic Operators// Working of arithmetic operators#include 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;}

Output

a+b = 13a-b = 5a*b = 36a/b = 2Remainder when a divided by b=1

The operators +, - and * computes addition, subtraction, and multiplication respectively as you might have expected.

In normal calculation, 9/4 = 2.25. However, the output is 2 in the program.

It is because both the variables a and b are integers. Hence, the output is also an integer. The compiler neglects the term after the decimal point and shows answer 2 instead of 2.25.

The modulo operator % computes the remainder. When a=9 is divided by b=4, the remainder is 1. The % operator can only be used with integers.

Suppose a = 5.0, b = 2.0, c = 5 and d = 2. Then in C programming,

// Either one of the operands is a floating-point numbera/b = 2.5 a/d = 2.5 c/b = 2.5 // Both operands are integersc/d = 2C Increment and Decrement Operators

C programming has two operators increment ++ and decrement -- to change the value of an operand (constant or variable) by 1.

Increment ++ increases the value by 1 whereas decrement -- decreases the value by 1. These two operators are unary operators, meaning they only operate on a single operand.

Example 2: Increment and Decrement Operators// Working of increment and decrement operators#include int main(){int a = 10, b = 100;float c = 10.5, d = 100.5;printf("++a = %d \n", ++a);printf("--b = %d \n", --b);printf("++c = %f \n", ++c);printf("--d = %f \n", --d);return 0;}

Output

++a = 11--b = 99++c = 11.500000--d = 99.500000

Here, the operators ++ and -- are used as prefixes. These two operators can also be used as postfixes like a++ and a--. Visit this page to learn more about how increment and decrement operators work when used as postfix.

C Assignment Operators

An assignment operator is used for assigning a value to a variable. The most common assignment operator is =

OperatorExampleSame as=a = ba = b+=a += ba = a+b-=a -= ba = a-b*=a *= ba = a*b/=a /= ba = a/b%=a %= ba = a%bExample 3: Assignment Operators// Working of assignment operators#include int main(){int a = 5, c;c = a; // c is 5printf("c = %d\n", c);c += a; // c is 10 printf("c = %d\n", c);c -= a; // c is 5printf("c = %d\n", c);c *= a; // c is 25printf("c = %d\n", c);c /= a; // c is 5printf("c = %d\n", c);c %= a; // c = 0printf("c = %d\n", c);return 0;}

Output

c = 5 c = 10 c = 5 c = 25 c = 5 c = 0C Relational Operators

A relational operator checks the relationship between two operands. If the relation is true, it returns 1; if the relation is false, it returns value 0.

Relational operators are used in decision making and loops.

OperatorMeaning of OperatorExample==Equal to5 == 3 is evaluated to 0>Greater than5 > 3 is evaluated to 1=Greater than or equal to5 >= 3 is evaluated to 1 b);printf("%d > %d is %d \n", a, c, a > c);printf("%d < %d is %d \n", a, b, a < b);printf("%d < %d is %d \n", a, c, a < c);printf("%d != %d is %d \n", a, b, a != b);printf("%d != %d is %d \n", a, c, a != c);printf("%d >= %d is %d \n", a, b, a >= b);printf("%d >= %d is %d \n", a, c, a >= c);printf("%d b) is %d \n", result);result = (a == b) && (c < b);printf("(a == b) && (c < b) is %d \n", result);result = (a == b) || (c < b);printf("(a == b) || (c < b) is %d \n", result);result = (a != b) || (c < b);printf("(a != b) || (c < b) is %d \n", result);result = !(a != b);printf("!(a != b) is %d \n", result);result = !(a == b);printf("!(a == b) is %d \n", result);return 0;}

Output

(a == b) && (c > b) is 1 (a == b) && (c < b) is 0 (a == b) || (c < b) is 1 (a != b) || (c < b) is 0 !(a != b) is 1 !(a == b) is 0

Explanation of logical operator program

(a == b) && (c > 5) evaluates to 1 because both operands (a == b) and (c > b) is 1 (true).(a == b) && (c < b) evaluates to 0 because operand (c < b) is 0 (false).(a == b) || (c < b) evaluates to 1 because (a = b) is 1 (true).(a != b) || (c < b) evaluates to 0 because both operand (a != b) and (c < b) are 0 (false).!(a != b) evaluates to 1 because operand (a != b) is 0 (false). Hence, !(a != b) is 1 (true).!(a == b) evaluates to 0 because (a == b) is 1 (true). Hence, !(a == b) is 0 (false).C Bitwise Operators

During computation, mathematical operations like: addition, subtraction, multiplication, division, etc are converted to bit-level which makes processing faster and saves power.

Bitwise operators are used in C programming to perform bit-level operations.

OperatorsMeaning of operators&Bitwise AND|Bitwise OR^Bitwise exclusive OR~Bitwise complementShift right

Visit bitwise operator in C to learn more.

Other OperatorsComma Operator

Comma operators are used to link related expressions together. For example:

int a, c = 5, d;The sizeof operator

The sizeof is a unary operator that returns the size of data (constants, variables, array, structure, etc).

Example 6: sizeof Operator#include int main(){int a;float b;double c;char d;printf("Size of int=%lu bytes\n",sizeof(a));printf("Size of float=%lu bytes\n",sizeof(b));printf("Size of double=%lu bytes\n",sizeof(c));printf("Size of char=%lu byte\n",sizeof(d));return 0;}

Output

Size of int = 4 bytesSize of float = 4 bytesSize of double = 8 bytesSize of char = 1 byte

Other operators such as ternary operator ?:, reference operator &, dereference operator * and member selection operator聽->聽will be discussed in later tutorials.