回文（palindrome）是指一个字符串从前面读和从后面读都一样，仅使用若干栈和队列、栈和队列的ADT函数以及若干个int类型和char类型的变量，设计一个算法来判断一个字符串是否为回文。假设字符串从标准输入设备一次读入一个字符，算法的输出结果为true或者false。-Palindrome (palindrome) refers to a string read from the front and from the back to read the same, only a number of stacks and queues, stacks and queues ADT functions and a number of variables of type int and char types, design an algorithm to determine a whether the string is a palindrome. Assuming a string from the standard input device reads a character, the output of the algorithm is true or false.