All expressions are stored in a file called "in.dat". The file contains a sequence of arithmetic expressions in the postfix form, one per line, printing the expression, calculating its value, and showing the result. Output: Hello! This is a postfix expression calculator. The value of "2 3 ^ 35 5 / -" is 1.0 The value of "1 2 + 3 * # 4 - 5 6 - + _" is 2.0 Bye-bye!