Question

我对所有关键字/保留字都有一个ArrayList，但是当打印输出时会打印出重复的关键字，我知道我可以使用HashSet来消除重复（I＆＃39;我们尝试过所有这些都没有，到目前为止没有工作）。但我认为contains方法负责打印重复项。

有关contains方法的替代方案的任何建议吗？

我顺便创建一个词法分析器，这是样本输入和输出

的ArrayList：

ArrayList<String> keywords = new ArrayList<>(Arrays.asList("auto","case","char","const","continue","default",
                            "do","double","else","break","enum","extern","float","for","goto",
                            "if","int","long","register","return","short","signed",
                            "sizeof","static","struct","switch","typedef","union",
                            "unsigned","void","volatile","while","then","int","endif"));

显示代码：

  System.out.print("Keywords:");
            for(int i =0; i<testarray.size(); i++){ 
            String gg = testarray.toString().replace(",","").replace("[","").replace("]","");

          String[] key = gg.trim().split(" ");
                 String gg1 = key[i];

                 if(keywords.contains(gg1)){

                     System.out.println(gg1+" ");
                 }
                 }

输入：

{

int a[3],t1,t2;

t1= 2 ; a[0]= 1; a[1]= 2; a[t1]= 3;

t2= - (a[2] + t1 * 6 ) / (a[2] - t1);

if t2 > 5 
then

print ( t2 );

else {

int t3 ; t3 = 99 ; t2 = -25 ;

print(- t1 +t2 * t3); 

} endif

}

输出： 关键字：int if then else int endif

阅读文件：

while((line = bufferedReader.readLine()) != null) {

                test = line.split(" ");

                testarray.addAll(Arrays.asList(test));

            }

Answer 1

我觉得你无所事事地做着复杂的事情：

<强>的ArrayList：

ArrayList<String> keywords = Arrays.asList("auto","case","char","const","continue","default",
                            "do","double","else","break","enum","extern","float","for","goto",
                            "if","int","long","register","return","short","signed",
                            "sizeof","static","struct","switch","typedef","union",
                            "unsigned","void","volatile","while","then","int","endif");

显示代码：

Set<String> keys = new HashSet<>();
for (String key : testarray) { 
    if(keywords.contains(key)) {
        keys.add(key);
    }
}

System.out.print("Keywords:");
for (String key : keys) {
    System.out.println(key + " ");
}

除了包含方法之外，还有哪些其他方法可以将arraylist与字符串文本文件进行比较？

1 个答案: