java急救 聊天系统中如何实现服务器端转发数据

Problem to solve:
Write a stack-based Calculator program in Java to support the following operators for integer and floating point data: addition, multiplication, division, subtraction; modulo and square-root. Also implement a print operator that prints out the entire stack and a pop operator that discards the top element on the stack. Your program should be in pure Java, and can use any of the standard Java Development Kit class library elements. Your operand stack should support mixed mode arithmetic and should promote integers to floating point numbers where appropriate. Implement appropriate exception handling to cope with malformed input from the user.

Specification:
Your program should accept textual input like:

144.0 sqrt
12.0
10 20 add
30
2 3 4 add mult
14
print
12
30
14
pop
pop
2.0
mult
24.0

Where the bolded lines are representative of your pro