word类：
public class word { //二元组类结构
private int typenum; //种别码
private String word;// 扫描得到的词
public int getTypenum() {
return typenum;
}
public void setTypenum(int typenum) {
this.typenum = typenum;
}
public String getWord() {
return word;
}
public void setWord(String word) {
this.word = word;
}
}
keywords类：
public class keywords {
private static String KEYWORDS = "关键字";//关键字判断
private word words;
private char[] input = new char[255];
private char[] token = new char[255];
private int p_input=0;//用于输入字符记数
private int p_token=0;//用于数字字符记数
private char ch; //获取单个字符
private String[] rwtab = {"begin", "if", "then","while", "do", "end", KEYWORDS};
public keywords(char [] input){
this.input = input;
}
public char ch_getCh(){ //获取下一个字符，用于多位符号判断
if (p_input<input.length){
ch=input[p_input];
p_input++;
}
return ch;
}
public void getbch(){ //获取标识符或空格的下一位字符
while ((ch == ' '||ch ==' ')&&(p_input<input.length)){
ch = input[p_input];
p_input++;
}
}
public void concat(){ //连接字符
token[p_token] = ch;
p_token++;
token[p_token]=' ';
}
public boolean letter() { //判断字符是否为字母
if(ch>='a'&&ch<='z'||ch>='A'&&ch<='Z')
return true;
else
return false;
}
public boolean num() { // 判断字符是否为数字
if(ch>='0'&&ch<='9')
return true;
else
return false;
}
public void re() {//回退一个字符
p_input--;
}
public String dtb() {
int num = token[0] - 48;
for(int i = 1; i < p_token; i++) {
num = num * 10 + token[i] - 48;
}
StringBuilder result = new StringBuilder(); //字符串连接
while(num>0) {
int r = num % 2;
int s = num / 2;
result.append(r);
num = s;
}
return result.reverse().toString();
}
public int reserve() { // 用于检查token字符串内是否存在关键字
int i=0;
while(rwtab[i].compareTo(KEYWORDS)!=0) {
if(rwtab[i].compareTo(new String(token).trim()) == 0) {//移除字符串两侧的空白字符或其他预定义字符
return i+1;
}
i++;
}
return 10;
}
public word scan() //开始扫描的大哥函数
{
token = new char[255];
word myWord = new word();
myWord.setTypenum(10);
myWord.setWord("");
p_token=0;
ch_getCh();
getbch();
if(letter()) { //找出标识符
while(letter()||num()) {
concat();
ch_getCh();
}
re();
myWord.setTypenum(reserve());
myWord.setWord(new String(token).trim());
return myWord;
}
else if(num()) {
while(num()) {
concat();
ch_getCh();
}
re();
myWord.setTypenum(11);
myWord.setWord(new String(token).trim()); //输出token中的数字串字符形式//
myWord.setWord(dtb()); //输出token中的数字串10进制值的二进制字符串形式
return myWord;
}
else
switch (ch) {
case '=':
myWord.setTypenum(25);
myWord.setWord("=");
return myWord;
case '+':
myWord.setTypenum(13);
myWord.setWord("+");
return myWord;
case '-':
myWord.setTypenum(14);
myWord.setWord("-");
return myWord;
case '*':
myWord.setTypenum(15);
myWord.setWord("*");
return myWord;
case '/':
ch_getCh(); //识别单行注释，个人用了30备注
if (ch == '/') {
while(ch_getCh() != ' ');
myWord.setTypenum(30);
myWord.setWord("\n");
return myWord;
}
//识别多行注释，个人用31来表示
if(ch=='*') {
String string = "";
while(true) {
if (ch == '*') {
if (ch_getCh() == '/') { //找到多行注释结尾
myWord.setTypenum(31);
myWord.setWord(string);
return myWord;
}
re();
}
if (ch_getCh() == ' ') { //找到多行注释的下一行
string += "\n";
}
}
}
re();
myWord.setTypenum(16);
myWord.setWord("/");
return myWord;
case ':':
ch_getCh();
if(ch=='=') {
myWord.setTypenum(18);
myWord.setWord(":=");
return myWord;
}
re();
myWord.setTypenum(17);
myWord.setWord(":");
return myWord;
case '<':
ch_getCh();
if(ch=='=') {
myWord.setTypenum(21);
myWord.setWord("<=");
return myWord;
}
else if (ch == '>') {
myWord.setTypenum(22);
myWord.setWord("<>");
return myWord;
}
re();
myWord.setTypenum(20);
myWord.setWord("<");
return myWord;
case '>':
ch_getCh();
if(ch=='=') {
myWord.setTypenum(24);
myWord.setWord(">=");
return myWord;
}
re();
myWord.setTypenum(23);
myWord.setWord(">");
return myWord;
case ';':
myWord.setTypenum(26);
myWord.setWord(";");
return myWord;
case '(':
myWord.setTypenum(27);
myWord.setWord("(");
return myWord;
case ')':
myWord.setTypenum(28);
myWord.setWord(")");
return myWord;
case ' ':
myWord.setTypenum(30);
myWord.setWord("\n");
return myWord;
case '#':
myWord.setTypenum(0);
myWord.setWord("#");
return myWord;
default:
concat();
myWord.setTypenum(-1);
myWord.setWord("其他字符 "" + new String(token).trim() + """);
return myWord;
}
}
}
main类：
import java.io.*;
import java.util.ArrayList;
import java.util.Scanner;
public class main {
private File inputFile;
private File outputFile;
private String fileContent;
private ArrayList<word> list = new ArrayList<>();
public main(String input,String output) {
inputFile = new File(input);
outputFile = new File(output);
}
public String getContent() {
StringBuilder stringBuilder = new StringBuilder();
try(Scanner reader = new Scanner(inputFile)) {
while (reader.hasNextLine()) {
String line = reader.nextLine();
stringBuilder.append(line + " ");
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return fileContent = stringBuilder.toString();
}
public void analyze(String fileContent) {
int over = 1;
word word = new word();
keywords scanner = new keywords(fileContent.toCharArray());
while (over != 0) {
word = scanner.scan();
list.add(word);
over = word.getTypenum();
} saveResult();
}
public void saveResult() {
if (!outputFile.exists())
try {
outputFile.createNewFile();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try(Writer writer = new FileWriter(outputFile)){
for (word word : list) {
writer.write("(" + word.getTypenum() + " ," + word.getWord() + ") ");
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
main Mains = new main("C:\Users\曾梓楷\Desktop\1.txt","C:\Users\曾梓楷\Desktop\output.txt");
Mains.analyze(Mains.getContent());
}
}
1.txt：
int main(){
int n,i,j,k;
printf("请输入班级人数：");
scanf("%d",&n);
struct student Stu[n];
for(i=0;i<n;i++){
printf("请按顺序输入第%d位学生姓名,学号和成绩: ",i+1);
printf("姓名 学号 成绩 ");
scanf("%s %d %d",Stu[i].name,&Stu[i].num,&Stu[i].cj);
}
for(i=0;i<n-1;i++)
for(j=0;j<n-i-1;j++)
if(Stu[j].cj<Stu[j+1].cj)
{
t=Stu[j];
Stu[j]=Stu[j+1];
Stu[j+1]=t;
}
printf("他们的排名如下: ");
for(i=0;i<n;i++){
printf("%s %d %d ",Stu[i].name,Stu[i].num,Stu[i].cj);
}