opmul.java

用JAVA写的计算一段数学表达式的程序

package net.csksoft.util.expcomp;
import java.util.*;
public class OpMul extends OperationToken {
//Finish CodeFans.net

	public boolean Calc(Stack<OpObj> objStack) {
		// TODO Auto-generated method stub
		return Calc2(objStack);
	}
	private boolean Calc2(Stack<OpObj> objStack)
	{
		OpObj a,b,ans;
		if (objStack.isEmpty()) return false;
		b = objStack.pop();
		if (objStack.isEmpty()) return false;
		a = objStack.pop();
		try
		{
			ans = (OpObj)new NumberToken(a.getValue() * b.getValue());
		}
		catch(Exception exp)
		{
			return false;
		}
		objStack.push(ans);
		return true;
	}
}