java - 如何验证这些表达式是否有效(所有括号配对 - 闭合)？

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这是我的第三次尝试，但预期结果不正确。

第一个表达式应该打印 -Bracket is Balanced。第二个表达式应该打印 -Bracket is NOT Balance.

注意需要使用 - charAt 或 要解决的子字符串，而不是数组或堆栈!因为我还没有学习这些!

import java.lang.*; 
import java.util.Scanner;


public class CheckBracketsPairs {
  public static void main(String[] args) {
    validateExpresion("(4+4)");
    validateExpresion("(4+4)*1)");
  }

  public static void validateExpresion(String s) {

    // MY CODES BELOW
    int count = 0;
    String open = "(";
    String close = ")";

    for (int i = 0, n = s.length(); i < n; i++) {
      Character c = s.charAt(i);

      if(c.equals(open)) {
        count++;
      }

      if(c.equals(close)) {
        count--;
      }
    }

      if(count == 0) {
        System.out.println("\n Expression:  " + s + ",      -Bracket is balanced");
      } else {
        System.out.println("\nBracket is NOT balanced");
      }
  }    
}

Answer 1

这里再次尝试。最后一行未按预期显示结果。
应该是 - -支架不平衡

public class CheckBracketsPairs  {
  public static void main(String[] args) {
    validateExpression(")((5+9)-2)");
    validateExpression("(2*6)-1)*(2^2)");
    validateExpression("(8^2)");
    validateExpression("(5+8^2))");  // This line computing?
    validateExpression("(5+8^2)(");  // Why is this line NOT computing?
  }

  public static void validateExpression(String s) {

    // MY CODES BELOW  
    int count = 0;
    char open = '(';
    char close = ')';

    for (int i = 0, n = s.length(); i < n; i++) {
      char c = s.charAt(i);

      if(c == open) {
        count++;
      }

      if (c == close) {
        count--;
        // If statement to check for closed brackets
        if (count < 0) {
          System.out.println("\nExpression:  " + s + "  -Bracket is NOT balanced");
          break;
        }
      }
    } 

    if (count == 0) {
      System.out.println("\nExpression:  " + s + "   -Bracket is balanced");
    }
  }    
}