Write a program that changes an infix expression to a postfix expression according to the following specifications.
1. The infix expression to be converted is in the input file in the format of one character per line, with a maximum of 50 lines in the file. For example, (3+2)*5 would be in the form:
2. The input file contains only one infix expression. There are no blank lines.
3. The program will only be designed to handle the binary operators +, -, *, /.
4. The operands will be one digit numerals.
5. The operators * and / have the highest priority. The operators + and - have the lowest priority. Operators at the same precedence level associate from left to right. Parentheses act as grouping symbols that over-ride the operator priorities.
6. The output file will have the postfix expression all on one line.
7. The input will be an expression with valid syntax.