wa.java

这个程序可以对输入的JAVA代码进行词法分析并输出二元式

package test;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class WA {
	private String temp = "";// 定义临时变量

	private String r = "";

	private String s = "";// 定义返回变量



	
	
	public String getTemp() {
		return temp;
	}



	public void setTemp(String temp) {
		this.temp = temp;
	}



	/**
	 * 取一字符
	 */
	public void inputProcess() {
		System.out.println("input end to stopInput...:");
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		while (true) {
			try {
				String input = in.readLine() + "";
				if (input.equals("end"))
					break;
				this.temp += input;
			} catch (IOException ex) {
				ex.getMessage();
			}
		}
		this.temp = temp.trim();
	}

	/**
	 * 取一字符
	 */
	public String getWord(int n, String temp) {
		return (temp.substring(n, n + 1));
	}

	/**
	 * 扫描
	 */
	
	
	public String scan() {
		int n = temp.length();
		String text = "", textTemp = "";
		boolean flag = true;
		// int t=0;
		// while (flag) {
		// if(++t==1)break;
		for (int i = 0; i <= n - 1; i++) { // 循环处理
			textTemp = getWord(i, temp);// 取一字符给textTemp
			/** texpTemp为空格，分隔符，运算符，取单词 * */

			try {
				if (i <= n - 5) {
					// if(temp.substring(i,i+2).equals("/*"));flag=false;
					// if(temp.substring(i,i+2).equals("*/"));flag=true;
					if ((temp.charAt(i) == '/') && (temp.charAt(i + 1) == '*'))
						flag = false;
					if ((temp.charAt(i) == '/') && (temp.charAt(i + 1) == '/'))
						flag = false;
					if ((temp.charAt(i) == '*') && (temp.charAt(i + 1) == '/')) {
						flag = true;
						i++;
						continue;
					}
				}
			} catch (Exception e) {
				System.out.print("" + e.getMessage());
			}
			if (flag) {
				if (isSpace(textTemp) || isOperation(textTemp)
						|| isCompartmentation(textTemp)) {
					if ((text.trim()).length() != 0) {
						if (isLetter(text)) { // 如果单词的开始第一个字符为字母，则判断是否为保留字，标识符，

							if (isReserveWords(text))// 是关键字，否标识符
								r += "\"" + text.trim() + "\"\t";
							else
								r += "\"" + text.trim() + "\"\t";
						} else if (isNumber(text))// 判断无符号整形数
							r += "\"" + text.trim() + "\"\t";
						text = "";
					}
					if (isOperation(textTemp)) { // 判断是否为运算符
						int j = i;
						while (isOperation(textTemp)) {
							text += textTemp;
							j++;
							textTemp = getWord(j, temp);
						}
						// i--;
						r += "\"" + text.trim() + "\"\t";
						text = "";
					}
					if (isCompartmentation(textTemp))
						r += "\"" + textTemp + "\"\t";// 判断是否为分隔符
				} else {
					text += textTemp;
				}
			}
		}
		if (text.trim().length() != 0) {
			r += "\"" + text.trim() + "\"\t";
		}
		// }
		return r;
	}

	/**
	 * 词法分析
	 */
	public String analyse() {
		int n = temp.length();
		String text = "", textTemp = "";
		boolean flag = true;
		while (flag) {
			for (int i = 0; i <= n - 1; i++) { // 循环处理
				textTemp = getWord(i, temp);// 取一字符给textTemp
				/** texpTemp为空格，分隔符，运算符，取单词 * */

				try {
					if (i <= n - 5) {
						// if(text.substring(i,i+2).equals("/*"));flag=false;
						// if(text.substring(i,i+2).equals("*/"));flag=true;
						if ((temp.charAt(i) == '/')
								&& (temp.charAt(i + 1) == '*'))
							flag = false;
						if ((temp.charAt(i) == '/')
								&& (temp.charAt(i + 1) == '/'))
							flag = false;
						if ((temp.charAt(i) == '*')
								&& (temp.charAt(i + 1) == '/'))
							flag = true;
					}
				} catch (Exception e) {
					System.out.print("" + e.getMessage());
				}
				if (isSpace(textTemp) || isOperation(textTemp)
						|| isCompartmentation(textTemp)) {
					if ((text.trim()).length() != 0) {
						if (isLetter(text)) { // 如果单词的开始第一个字符为字母，则判断是否为保留字，标识符，

							if (isReserveWords(text))// 是关键字，否标识符
								s += "（1关键字,\"" + text.trim() + "\")\n";
							else
								s += "（2标识符,\"" + text.trim() + "\")\n";
						} else if (isNumber(text))// 判断无符号整形数
							s += "（3数字,\"" + text.trim() + "\")\n";
						text = "";
					}
					if (isOperation(textTemp)) { // 判断是否为运算符
						while (isOperation(textTemp)) {
							text += textTemp;
							i++;
							textTemp = getWord(i, temp);
						}
						i--;
						s += "（4运算符,\"" + text.trim() + "\")\n";
						text = "";
					}
					if (isCompartmentation(textTemp))
						s += "（5分隔符,\"" + textTemp + "\")\n";// 判断是否为分隔符
				} else {

					text += textTemp;
				}
			}
		}
		return s;
	}

	/**
	 * 判断是否为分隔符方法
	 */
	public boolean isCompartmentation(String text) {
		String Compartmentation[] = { ",", ";", "{", "}", "(", ")", "#" };

		for (int i = 0; i < Compartmentation.length; i++)
			if (text.equals(Compartmentation[i]))
				return true;
		return false;
	}

	/**
	 * 判断是否为保留字方法
	 */
	public boolean isReserveWords(String text) {
		String reserverwords[] = { "if", "main", "int", "for", "while", "do",
				"return", "break", "continue", "printf" };

		for (int i = 0; i < reserverwords.length; i++)
			if (reserverwords[i].equals(text))
				return true;
		return false;

	}

	/** 判断是否为运算符方法* */

	public boolean isOperation(String text) {
		String operation[] = { "+", "-", "=", "++", "--", "*", "/" };

		for (int i = 0; i < operation.length; i++)
			if (text.equals(operation[i]))
				return true;
		return false;
	}

	/** 判断是否为空格方法* */

	public boolean isSpace(String text) {
		return (text.equals(new String(" ")));
	}

	/** 判断是否为字母方法* */

	public boolean isLetter(String text) {
		if (text.trim().charAt(0) >= 'a'
				&& (text.toLowerCase()).charAt(0) <= 'z')
			return true;
		return false;
	}

	/** 判断是否为数字方法* */

	public boolean isNumber(String text) {

		for (int i = 0; i < text.length(); i++) {
			if (!(text.charAt(i) >= '0' && text.charAt(i) <= '9'))
				return false;
		}
		return true;
	}

	public static void main(String[] args) throws IOException {
		WA ioword = new WA();
		ioword.inputProcess();
		System.out.print("扫描结果:\n" + ioword.scan());
		System.out.println();
		//System.out.print("词法分析结果:\n"+ioword.analyse());

	}
}