Question

Explain the results of the following expressions (you may want to show each step of evaluation):

• 4 + 5 * 6 + 7 / 8

• 4 + 5 * 6 < 7 / 8

• 4 + 5 > 6 && 7 < 8

• 1 && 0

Answer 1

(1)   4 + 5 * 6 + 7 / 8

Answer-

  Step (i) To solve this question first we have to find the precedence of all operator

  So according to precedence of operator multiplication (*) and divide( /) have a higher precedence then plus ( + ) and ( - ) . so first we have to calculate multiplication and divide.

After solving the multiplication and divide-

  We know 5 * 6 is 30 and 7 / 8 is 0.

  So 4 + 30 + 0

Step (ii) - now we have to calculate + operation so if one or more operator having same precedence then it will solve with the help of associativity. So in our condition associativity of + operator is Left to right so it will solve left to right.

   4 + 30 + 0 (solve Left to Right)

  So 34 is answer.

(2)   4 + 5 * 6 < 7 / 8

    

In this example we have two type of operator Arithmatic and relational operator.

So according to rule Arithmatic operators have greater precedence then Relational operator.

So first we calculate +, * and /.

   So we know * and / having greater precedence so they solve first.

We know 5 * 6 is 30 and 7 / 8 is 0.

4 + 30 < 0

Now calculate + operator

34 < 0 (this condition is false so it return 0)

Now we calculate relational operator and its return 0 and 1 value.

So in our case condition is false.

So 0 is answer.

(3) 4 + 5 > 6 && 7 < 8

Step ( i)   We know Arithmatic operator have greater precedence then Relational and logical And operators.

So first solve + operator-

   9 > 6 && 7<8

Step ( ii ) now we know relational operator having more precedence then logical Operator so-

       We know 9 is greater then 9 and 7 is less then 9 so both return 1.

1 && 1

In && operator if both digit is non zero then it return True. in our case bot digit is non zero .

So 1 (True) is Answer

(4)   1 && 0

      

We know that logical && operator return true (1) if both digit is non zero . in our case first digit is one that is non zero but second digit is 0.

So it return false(0).

So 0 is answer