Operators are special symbols used for specific purposes. C++ provides many operators for manipulating data.
Generally, there are six type of operators : Arithmetical operators, Relational operators, Logical operators, Assignment operators, Conditional operators, Comma operator.
Arithmetical operators +, -, *, /, and % are used to performs an arithmetic (numeric) operation.
You can use the operators +, -, *, and / with both integral and floating-point data types. Modulus or remainder % operator is used only with the integral data type.
Operators that have two operands are called binary operators.
C++ provides two unary operators for which only one variable is required.
a = - 50; a = + 50;
Here plus sign (+) and minus sign (-) are unary because they are not used between two variables.
The relational operators are used to test the relation between two values. All relational operators are binary operators and therefore require two operands. A relational expression returns zero when the relation is false and a non-zero when it is true. The following table shows the relational operators.
|<=||Less than or equal to|
|>=||Greater than or equal to|
|! =||Not equal to|
The logical operators are used to combine one or more relational expression. The logical operators are
The assignment operator '=' is used for assigning a variable to a value. This operator takes the expression on its right-hand-side and places it into the variable on its left-hand-side. For example:
m = 5;
The operator takes the expression on the right, 5, and stores it in the variable on the left, m.
x = y = z = 32;
This code stores the value 32 in each of the three variables x, y, and z.
in addition to standard assignment operator shown above, C++ also support compound assignment operators.
Compound Assignment Operators
|+ =||A + = 2||A = A + 2|
|- =||A - = 2||A = A - 2|
|% =||A % = 2||A = A % 2|
|/=||A/ = 2||A = A / 2|
|*=||A * = 2||A = A * 2|
Increment and Decrement Operators
C++ provides two special operators viz '++' and '--' for incrementing and decrementing the value of a variable by 1. The increment/decrement operator can be used with any type of variable but it cannot be used with any constant. Increment and decrement operators each have two forms, pre and post.
The syntax of the
increment operator is:
The syntax of the decrement operator is:
In Prefix form first variable is first incremented/decremented, then evaluated
In Postfix form first variable is first evaluated, then incremented/decremented
int x, y; int i = 10, j = 10; x = ++i; //add one to i, store the result back in x y = j++; //store the value of j to y then add one to j cout << x; //11 cout << y; //10
The conditional operator ?: is called ternary operator as it requires three operands.
The format of the conditional operator is:
Conditional_ expression ? expression1 : expression2;
If the value of conditional expression is true then the expression1 is evaluated, otherwise expression2 is evaluated.
int a = 5, b = 6; big = (a > b) ? a : b;
The condition evaluates to false, therefore big gets the value from b and it becomes 6.
The comma operator
The comma operator gives left to right evaluation of expressions. When the set of expressions has to be evaluated for a value, only the rightmost expression is considered.
int a = 1, b = 2, c = 3, i; // comma acts as separator, not as an operator i = (a, b); // stores b into i
Would first assign the value of a to i, and then assign value of b to variable i. So, at the end, variable i would contain the value 2.
The sizeof operator
As we know that different types of Variables, constant, etc. require different amounts of memory to store them The sizeof operator can be used to find how many bytes are required for an object to store in memory. For example
sizeof (char) returns 1 sizeof (float) returns 4
the sizeof operator determines the amount of memory required for an object at compile time rather than at run time.
The order of Precedence
The order in which the Arithmetic operators (+,-,*,/,%) are used in a. given expression is called the order of precedence. The following table shows the order of precedence.
*, /, %
The following table shows the precedence of operators.
|++, --(post increment/decrement)||
|++ (Pre increment) -- (Pre decrement), sizeof ( ), !(not), -(unary), +(unary)|
|<, <=, >, >=|