stactmachine.java

java 计算实现代码 利用堆栈实现 java 计算实现代码

package org.yancan;
public class stactMachine
{    
 String stactcode ="";
    arrayStact tempstact = new arrayStact();
 
 public stactMachine(String temp)
 { 
  stactcode = temp;
 }
    public void outputstactcode()
 {
     if(stactcode=="")
      System.out.println("expression is wrong, so you must correct it~~!Then go on~!\n");
        else
     {
       for(int i=0;i<stactcode.length();i++)
       System.out.print(stactcode.charAt(i));
       System.out.println("\n\n");
    }
 }
    public void outputcompute()
 {   
     if(stactcode=="")
       ;
     else
      {
     String[] part = stactcode.split("\n");
     for(int j=0;j<part.length;j++)
  {
     if(part[j].charAt(0)=='P')
          tempstact.push(Integer.parseInt( part[j].substring(5, part[j].length()) ) );
     else
     {   
     // int tempa,tempb,tempc;
    	 float tempa,tempb,tempc;
         tempb=tempstact.pop();
         tempa=tempstact.pop();
      
         if(part[j].charAt(0)=='A')
      {
       tempc=tempa+tempb;
          System.out.println(""+ formatoutput(tempa) + "+" + formatoutput(tempb) +" = "+ tempc+"\n");
      }
      if(part[j].charAt(0)=='S')
      {
       tempc=tempa-tempb;
       System.out.println(""+ formatoutput(tempa) + "-" + formatoutput(tempb) +" = "+ tempc+"\n");
      }
      if(part[j].charAt(0)=='M')
      {
       tempc=tempa*tempb;
       System.out.println(""+ formatoutput(tempa) + "*" + formatoutput(tempb) +" = "+ tempc+"\n");
      }
      if(part[j].charAt(0)=='D')
      {
       tempc=tempa/tempb;
       System.out.println(""+ formatoutput(tempa) + "/" + formatoutput(tempb) +" = "+ tempc+"\n");  
      }   
     }//end inner else
  }// end outer else
    }//end for 
 }
   // private String formatoutput(int temp)
    private String formatoutput(float temp)
    {
     if(temp<0)
      return "("+temp+")";
     else
      return ""+temp+"";
    }
}