算法，一个算术表达式是由操作数(operand)、运算符(operator)和界限符(delimiter)组成的。假设操作数是正实数，运算符只含加减乘除等四种运算符，界限符有左右括号和表达式起始、结束符“#”，如：#（7+15）*（23-28/4）#。引入表达式起始、结束符是为了方便。编程利用“算符优先法”求算术表达式的值。-Algorithm, an arithmetic expression is made up of operands (operand), operator (operator), and bound (delimiter). Assuming operand is a positive real number, the operator only containing such as addition, subtraction, multiplication and division four operator, boundary character around braces and expression of initiation and terminator#, such as:# 7+15* (23-28/4)#. The introduction of the start of the expression, the end of the character is to facilitate. Programming using the operator precedence method to find the value of the arithmetic expression.