使用堆栈检查.txt文件('s,{'s,['s等 - Java

时间:2011-11-14 03:17:01

标签: java file stack

我正在尝试在java中编写一个方法来搜索我为特定字符导入的文本文件。该文件实际上是我设计并转换为.txt文件的java程序。

当找到一个开口支架/支架时,我应该将它添加(推)到一个堆栈,然后当找到相应的关闭支架/支架时,我应该从堆栈中移除(弹出)它。

目的是查看我是否有正确数量的)}]>(,{{ 1}},{[。如果它们都匹配,则该方法应返回true,否则返回false。

任何人都知道我怎么写这个?

1 个答案:

答案 0 :(得分:2)

这是用于平衡输入文本文件中括号的示例实现

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Stack;

public class BalanceBrackets {
    private Stack<Character> symbolStack;

    public void balance(String inputText) {
        symbolStack = new Stack<Character>();
        for (int index = 0; index < inputText.length(); index++) {
            char currentSymbol = inputText.charAt(index);
            switch (currentSymbol) {
            case '(':
            case '[':
            case '{': 
                symbolStack.push(currentSymbol);
                break;

            case ')':
            case ']':
            case '}':
                if (!symbolStack.isEmpty()) {
                    char symbolStackTop = symbolStack.pop();
                    if ((currentSymbol == '}' && symbolStackTop != '{')
                            || (currentSymbol == ')' && symbolStackTop != '(')
                            || (currentSymbol == ']' && symbolStackTop != '[')) {
                        System.out.println("Unmatched closing bracket while parsing " + currentSymbol + " at " + index+1);
                        return;
                    }
                } else {
                    System.out.println("Extra closing bracket while parsing " + currentSymbol + " at character " + index+1);
                    return;
                }
                break;
            default:
                break;
            }
        }
        if (!symbolStack.isEmpty())
            System.out.println("Insufficient closing brackets after parsing the entire input text");
        else 
            System.out.println("Brackets are balanced");
    }

    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new FileReader("D://input.txt"));
        String input = null;
        StringBuilder sb = new StringBuilder();
        while ((input = in.readLine()) != null) {
            sb.append(input);
        }
        new BalanceBrackets().balance(sb.toString());
    }
}