NCERT Computer: Chapter 7 – Introduction to C + + Part 6

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Logical operators

The logical operators are used to combine one or more relational expression. The following table shows the logical operators.

Image of Logical operators

Image of Logical Operators

Image of Logical operators

The NOT operator is called the unary operator because it requires only one operand.

Example 2

The first expression evaluates to false and second expression evaluates to true. Therefore, the final expression is false.

In AND operation, if any one of the expression is false, the entire expression is false

In OR operation, if any one of the expression is true, the entire expression is true.

In NOT operation, only one expression is required.

If the expression is true, the NOT operation of true is false and vice versa.

Unary operators

C++ provides two unary operators for which only one variable is required.

For Example 3

Here plus sign and minus sign are unary because they are not used between two variables.

Assignment operator

The assignment stores the value of the expression on the right hand side of the equal sign to the operand on the left hand side.

Example 4

In addition to standard assignment operator shown above, C++ also supports compound assignment operators.

Let us study the use of compound assignment operators in the following table:

Image of Assignment operator

Image of Assignment Operator

Image of Assignment operator

Example 5

/ / first

/ / second

In the second statement, the value of x is 7

Conditional operator

The conditional operator is called ternary operator as it requires three operands. The format of the conditional operator is:

Conditional_expression? expression: expression 2;

If the value of Conditional_expression is true then the expression 1 is evaluated, otherwise expression 2 is evaluated.

Example 6

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.

It enables to put more than one expression separated by comma on a single line.

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