C语言编程，用Visual C编程，接受用户输入的一个四则运算表达式，输出其结果。例如用户输入表达式(5‐1/5)*5，则输出结果24.00，输出时精确到小数点后两位-C language programming, using Visual C programming, to accept user input of a four operational expression, the output results. For example, the user enters the expres