Write an algorithm to evaluate postfix expression.

1.	Write an algorithm to evaluate postfix expression.
Answer» Step 1: Start Step 2: Check all symbols from left to right and repeat steps 3 & 4 for each symbol of expression ‘E’ until all symbols are over. (i) If the symbol is an operand, push it onto a stack. (ii) If the symbol is an operator then: (iii) Pop the top two operands from the stack and apply an operator in between them. (iv) Evaluate the expression and place the result back on the stack. Step 3: Set result equal to a top element on the stack. Step 4: Stop

Answer»

Step 1: Start

Step 2: Check all symbols from left to right and repeat steps 3 & 4 for each symbol of expression ‘E’ until all symbols are over.

(i) If the symbol is an operand, push it onto a stack.

(ii) If the symbol is an operator then:

(iii) Pop the top two operands from the stack and apply an operator in between them.

(iv) Evaluate the expression and place the result back on the stack.

Step 3: Set result equal to a top element on the stack.

Step 4: Stop

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