Java中缀表达式转后缀表达式实现方法详解

/*
 * 中缀转后缀
 */
public void toPostfix() {
  // TODO Auto-generated method stub
  int sum = 0 ;//用于记入”（）“总个数
  int j = 0 ;//用于读到”）“时循环出栈
  String outStack = null;
  charnum.push(null);
  for( int i = 0 ; i  zanshi = new Stack<>();
  for(int i = 0 ; i 

  /*
   * 后缀表达式求值
   */
  public String postfix() {
    int a = 0 , b = 0;//栈中弹出的两数
    int sum ;//求两数运算
    for (int i = 0; i 

//注：代码中有很多输出 方便读者实时查看运算过程中 各内容
// 这些输出导致篇幅较长 大家看明白后 删去即可
public class Calculate {
 private Stack num; //后缀用栈 中转后数字栈
 private Stack charnum;//中转后字符栈
 private String []calculate;//存字符串数组
 private int calculateLength;//字符串数组长度
 public Calculate() {
  // TODO Auto-generated constructor stub
  num = new Stack<>(); //后缀用栈 中转后数字栈
  charnum = new Stack<>();//中转后字符栈
  calculate = new String[1000];//存字符串数组
  calculateLength = 0 ;//字符串数组长度
 }
 //转字符串数组
 public void toStringArray(String input) {
  boolean pointFalg = false;
  char charArray[] = input.toCharArray();
  double number = 0;//用于导入多位数
  int j = 0 ;//用于计入当前字符串数组的位数
  int sizeOfArray = charArray.length;
  int pointBelow =1
    ;
  for(int i = 0 ; i  '9' ) && charArray[i+1] != '.'){
     if ( (i + 1) != sizeOfArray && charArray[i+1] == ' ') {
      i++;
     }
     calculate[j++] = String.valueOf(number);
     System.out.println("number:" + number);
     number = 0 ;
     pointFalg = false;
    }
   }
   System.out.println("---z->" + calculate[i]);
  }
  calculateLength = j-- ;//不--会将‘#'存入
 }
 public void outPutCalculate() {
  for(int i = 0 ; i  zanshi = new Stack<>();
//      num.pop();
  for(int i = 0 ; i 

public class Main {
  public static void main(String[] args) {
    Calculate text = new Calculate();
    text.toStringArray("1+2*(3-1+2)-3");
    text.outPutCalculate();
    text.toPostfix();
    System.out.println(text.postfix());
  }
}

public class Main {
  public static void main(String[] args) {
    Calculate text = new Calculate();
    text.toStringArray("1 2 3 1-2+*+3-");
    text.outPutCalculate();
    System.out.println(text.postfix());
  }
}