实现计算器的功能。用户根据程序的提示，输入数字，选择要进行的计算，可以进行加、减、乘、除运算，简单的四则运算及其测试，开平方，华氏温度与摄氏温度之间的相互转换等运算。-Achieve the function of the calculator. The program prompts, enter numbers, select the calculation to be carried out, you can add, subtract, multiply, and in addition to the calculation, simple arithmetic test, open square, between the Fahrenheit and Celsius temperature conversion operations.