a31任意输入一行字符串判断这个字符串的情况程序简单易懂-a31 arbitrary input line of string to determine the string program easy to understand

构造LL(1)语法分析程序，任意输入一个文法符号串，并判断它是否为文法的一个句子。程序要求为该文法构造预测分析表，并按照预测分析算法对输入串进行语法分析，判别程序是否符合已知的语法规则，如果不符合（编译出错），则输出错误信息-Construct LL (1) parser, enter an arbitrary string of grammar symbols, and determine if it is a sentence grammar. Procedural requirements

The sine wave is important in physics because it retains its wave shape when added to another sine wave of the same frequency and arbitrary phase and magnitude. It is the only periodic waveform that has this property. This property leads to its impor