左眼皮跳跳

Problem Description 读入一个只包含 +, -, *, / 的非负整数计算表达式，计算该表达式的值。   Input 测试输入包含若干测试用例，每个测试用例占一行，每行不超过200个字符，整数和运算符之间用一个空格分隔。没有非法表达式。当一行中只有0时输入结束，相应的结果不要输出。   Output 对每个测试用例输出1行，即该表达式的值，精确到小数

Problem Description As the new term comes, the Ignatius Train Station is very busy nowadays. A lot of student want to get back to school by train(because the trains in the Ignatius Train Station is t