C++ Operators

What will be the output of the following code?

int x = 12, y=12;

cout << (x <= y) << endl;

• 0

• 1

• true

• false

Answer explanation

<= means "less than or equal to", it will be true if any one is satisfied

What will be the output of the following code?

int x = 2;

cout << x++ << endl;

• 2

• 3

• Compilation Error

• Compiler dependent output

Answer explanation

x++ means "use and then increment"

so x is used (supplied to cout) before incrementing

What will be the output of the following code?

int x = 2;

cout << --x << endl;

• 1

• 2

• Compilation Error

• Compiler dependent output

Answer explanation

--x means first decrement and then use.

so x is decremented first and then given to cout

What will be the output of the following code?

int x = 4+5*7-6%2/2;

    cout << x;

• 39

• 0

• 38

• 40

Answer explanation

*, % and / have higher precedence than + and -

4+5*7-6%2/2

=4+35-0/2

=4+35-0

=39

What will be the output of the following code?

cout << (5<7 && 7>3) << endl;

• 0

• 1

• true

• false

Answer explanation

In logical operator && (AND), both the sides of operator should result in true to get true.

true in c++ is printed as 1.

What will be the output of the following code?

int x=5, y=6, z=7;

cout << (x>y && ++y) << endl;

cout << y << endl;

• 0

  6

• 1

  7

• 1

  6

• 0

  7

Answer explanation

int x=5, y=6, z=7;

x>y && ++y

since x>y is false and for && it is the sufficient condition to get result, other side of the && will not be evaluated.

This (x>y && ++y) expression will give 0 (false).

The value of y will remain 6.

What will be the output of the following code?

int x=5, y=6, z=7;

cout << (x<y || ++y) << endl;

cout << y << endl;

• 0

  6

• 1

  7

• 1

  6

• 0

  7

Answer explanation

int x=5, y=6, z=7;

x<y || ++y

since x<y is true and for || it is the sufficient condition to get result, other side of the || will not be evaluated.

This (x<y || ++y) expression will give 1 (true).

The value of y will remain 6.

What will be the output of the following code?

int y = 5;

    int x = y = y + 5;

    cout << x << " " << y << endl;

• 10 10

• 10 5

• compilation error

• 5 5

Answer explanation

int y = 5;

int x = y = y + 5;

y+5 is 5, it is assigned to y and value of y is assigned to x

What will be the output of the following code?

int y;

    y = 1,2,3;

    cout << y << endl;

• 1

• 2

• compilation error

• 3

Answer explanation

int y;

y = 1,2,3;

precedence of "=" is higher than "," so y = 1 is executed first.

What will be the output of the following code?

int y = -20;

    cout << !y << endl;

• 1

• 2

• compilation error

• 3

Answer explanation

int y;

y = (1,2,3);

(1,2,3) is evaluated first because it is enclosed in brackets.

2 will overwrite 1 and 3 will overwrite 2, finally 3 will be assigned to y.