进行结果小于65535的加减混合运算，如果输入的不是加减符号及数字将会出现错误，并提示重新输入，按esc可以退出程序。-The result is less than 65535 mixed addition and subtraction operations, if the input is not a plus or minus sign and the number will be errors, and prompts to re-enter, press esc to exit th