Question

QUICK ANSWER PLS

What is the result of the following prefix expression? + 10 + 54

Answer 1

Answer :

EVALUATE_PREFIX(STRING)

Step 1: Start by picking up literals from the end

Step 2: If element is an operand push it to Stack

Step 3: If the element is an operator pop two elements from the Stack.

Operate on these elements according to the operator, and push the result  back to the Stack

Step 4: Move left and process elements as shown in step 2 and 3 until all are scanned in the expression.

Step 5: The Result is stored at the top of the Stack

Explanation :

+ 10 * 5 4

1. Push 4 to stack

2. Push 5 to stack. Stack contains

5

4

3. * is operator. Pop two elements, multiply and push to stack. Stack contains

20

4. Push 10 to stack. Stack contains

10

20

5. + is operator. Pop two elements, add and push to stack. Stack contains

30

6. Result is 30