Evaluation of Postfix Expression

1.read only one input symbol at a time from postfix expression.
2.if input symbol is operand ,push operand in to stack(before pushing convert that into integer).
3.if input symbol is operator ,pop two operands from stack perform operation and push result into stack.
4.repeat the process till the expression become empty.
5.finally result will be stored in the top of the stack(top==0).