Operators And Its Precedence

Question 1

Operator’s precedence

Answer 1

The order in which the operators are evaluated in a compound expression

Question 2

Precedence

Answer 2

All operators in C++ are assigned a level of precedence, operators with higher level are evaluated first

Question 3

Operator associativity

Answer 3

It tells the compiler the direction of evaluation of operators that are assigned the same level of precedence

Question 4

Precedence levels

Answer 4

1 is highest, 17 is lowest

Question 5

Parenthesis

Answer 5

Used to make it clear how the expression should be evaluated, even if they are unneccesary

Question 6

Unary arithmetic operators

Answer 6

Plus and minus, should be placed immediately preceding the operand

Question 7

Unary minus

Answer 7

Returns the operand multiplied by -1

Question 8

Unary plus

Answer 8

Returns the value of the operand

Question 9

Binary arithmetic operators

Answer 9

Addition, subtraction, multiplication, division and modulus (remainder%)

Question 10

Floating point division

Answer 10

Occurs when either of the operands are floating poating point values, returns a floating point value and the fraction is kept

Question 11

Integer division

Answer 11

If both of the operands are integers it drops fractions and returns an integer value.

Question 12

Using static_cast<> to do floating point division with integers

Answer 12

Use static_cast<> to convert an integer to floating point number

Question 13

Dividing by zero

Answer 13

Will generaly cause the program to crash

Question 14

Arithmetic assignment operators

Answer 14

Assignment, additional assignment, subtraction assignment, multiplication assignment, division assignment and modulus assignment

Question 15

Modulus operator

Answer 15

Operator that returns the ramainder after doing an integer division, only works with integer operands

Question 16

Use for modulus

Answer 16

For testing whether a number is evenly divisable by another number

Question 17

Modulus with negative numbers

Answer 17

Returns result with the sign of x (x/y)

Question 18

Exponent operator (^)

Answer 18

Bitwise XOR operator

Question 19

Exponent in C++

Answer 19

C++ doesn’t include exponent operator, exponents are done with #include the header and using the pow() function

Question 20

Parameters and return value of pow()

Answer 20

Type double, due to rounding errors in floating point numbers, the result may not be precise.

Question 21

Incrementing and decrementing

Answer 21

Adding 1 to and subtracting 1 from

Question 22

Prefix increment/decrement

Answer 22

If we use it the operand is incremented/decremented and the expression evaluates to the value of the operand

Question 23

Postfix increment/decrement

Answer 23

A copy of the opedand is made, yhe operand is incremented/decremented and the copy is evaluated

Question 24

Side effects

Answer 24

If a function or expression does anithing that persists beyond the life of the function/ expression itself

Question 25

Common side effects

Answer 25

Changing the value of objects, doing input or output or updating a graphical user interface

Question 26

Comma operator

Answer 26

Allows to evaluate multiple expressions when a single expression is allowed, evaluates the left then the right operand and returns the result of the right

Question 27

Other use of comma

Answer 27

As a seperator, it doesn’t invoke the comma operator

Question 28

Conditional operator ?:

Answer 28

Ternary operator, provides a shorthand method for doing particular type of if/else statement

Question 29

Paranthesization of the conditional operator

Answer 29

Conditional operator has low precidence, so it is common convention to paranthesize at least the conditional part of the operator

Question 30

Evaluation of the conditional operator

Answer 30

As an expression, must match the type of both expressions or the second expression must be convertable to the type of the first

Question 31

Use of conditional operator

Answer 31

• ehen we need a conditional initializer or assignment for a variable
• to pass conditional value to a function
• simple conditionals
• do Not use for complex if/else statements

Question 32

Relational operators

Answer 32

Operators that let you compare two values, it evaluates to a boolean value

Question 33

Comparison and equality with floating point

Answer 33

Comparison can be done but it can’t be too precise, equality should be avoided.

Question 34

Floating point equality

Answer 34

Can be done by using a function that looks to see if two numbers are almost the same

Question 35

Epsilon

Answer 35

Small positive number, value that represents “close enough”

Question 36

std::abs()

Answer 36

Function in the header that returns the absolute value of its argument *downside-everytime we call the function we have to pick an epsilon appropriate to the input

Question 37

Donald knut method

Answer 37

Epsilon is relative to a or b, it is calculated by algorithams choice of the larger a or b and multiplies it by epsilon in percents

Question 38

Inequality

Answer 38

Call the function and use logical NOT operator

Question 39

Approximately equal()

Answer 39

Will work in most cases, but not well when the numbers aproach zero

Question 40

Logical operators

Answer 40

To test multiple conditions

Question 41

C++ logical operators

Answer 41

Logical NOT!, OR||, AND&&

Question 42

Logical not

Answer 42

Flips a boolean value from true to false and vice versa

Question 43

Logical not with a result of operators

Answer 43

The operators and operands need to be in parenthesis

Question 44

Logical or

Answer 44

Used to test whether either of two conditions is true, if either or both are true it returns true

Question 45

Logical and

Answer 45

Used to test whether both operands are true

Question 46

Short circut evaluation

Answer 46

Used for optimization, when operator returns a value only on the basis of the evaluation of the first operand

Question 47

Mixing logical and and or

Answer 47

And has higher precidence so it will evaluate first unles parenthesized, also evaluates from right to left

Question 48

De Morgan’s law

Answer 48

Distribution of logical not can't be done like
*!(x&&y)=!x&&!y
You must flip logical Not and And like
*!(x&&y)=!x||!y
*!(x||y)=!x&&!y

Question 49

Logical exclusive XOR operator

Answer 49

Not in c++, it can be mimicked with logical not operator
It is used to test whether odd number of conditions are true, if we don’t work with boolean we can static_cast them into boolean.