Question

infix postfix example and definition
.
proper concept​

Answer 1

Answer:

Explanation:

Infix expression: The expression of the form a op b. When an operator is in-between every pair of operands.

Postfix expression: The expression of the form a b op. When an operator is followed for every pair of operands.

The compiler scans the expression either from left to right or from right to left.  

Consider the below expression: a op1 b op2 c op3 d  

If op1 = +, op2 = *, op3 = +

The compiler first scans the expression to evaluate the expression b * c, then again scans the expression to add a to it. The result is then added to d after another scan.

The repeated scanning makes it very in-efficient. It is better to convert the expression to postfix(or prefix) form before evaluation.

The corresponding expression in postfix form is abc*+d+. The postfix expressions can be evaluated easily using a stack. We will cover postfix expression evaluation in a separate post.