SDP04-03例子代码.rar

import java.util.*; public class Calculator { private String statement; private Node node; public void build(String statement) { Node left=null,right=null; Stack stack=new Stack(); String[] statementArr=statement.split(" "); for(int i=0;i<statementArr.length;i++) { if(statementArr[i].equalsIgnoreCase("*")) { left=(Node)stack.pop(); int val=Integer.parseInt(statementArr[++i]); right=new ValueNode(val); stack.push(new MulNode(left,right)); } else if(statementArr[i].equalsIgnoreCase("/")) { left=(Node)stack.pop(); int val=Integer.parseInt(statementArr[++i]); right=new ValueNode(val); stack.push(new DivNode(left,right)); } else if(statementArr[i].equalsIgnoreCase("%")) { left=(Node)stack.pop(); int val=Integer.parseInt(statementArr[++i]); right=new ValueNode(val); stack.push(new ModNode(left,right)); } else { stack.push(new ValueNode(Integer.parseInt(statementArr[i]))); } } this.node=(Node)stack.pop(); } public int compute() { return node.interpret(); } }