amaan-mohib / stacker Goto Github PK

Practically, these are used in calculators, as they increase the speed of calculations.

1. Scan each element of the expression (X) from left to right and repeat steps 2 to 5 until the stack is empty.
2. If an operand is encountered add it to the resultant string (Y).
3. If a left parenthesis ( "(" ) is encountered then push it to the stack.
4. If an operator is encountered then:
   1. Repeatedly pop from stack and add it to Y which has the same or higher precedence than the next operator.
   2. Push operator to the stack.
5. If a right parenthesis is encountered then:
   1. Repeatedly pop from the stack and to Y until a left parenthesis is encountered.
   2. Pop the left parenthesis.
6. END

1. Scan the expression (X) and reverse it, also replace "(" to ")" and vice versa.
2. Perform InFix to PostFix conversion on the reversed expression.
3. Finally, reverse the obtained PostFix expression, resulting in the PreFix expression.
4. END

1. Scan the expression (X) from left to right and repeat steps 2 to 4.
2. If an operand is encountered then push the element to stack.
3. If an operator is encountered then pop two operands and evaluate based on the operator.
4. Push the answer to the stack.
5. Finally, pop the element which is the answer.
6. END

1. Scan the expression (X) and reverse it.
2. Perform PostFix evaluation on the expression.
3. The resulting value is the answer.
4. END