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最新推荐文章于 2022-04-28 15:22:02 发布

J_Factory

最新推荐文章于 2022-04-28 15:22:02 发布

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分类专栏： Java 文章标签： string n2 import class c

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import java.util.Stack;

public class Calcu{

	Stack <Integer>num;

	Stack <String>exp;

	String expression="7+(8+2*2)/3-1=";

	public Calcu(){

		num=new Stack<Integer>();

		exp=new Stack<String>();

	}

	public void calculate(){

		char t;

		int s;

		int len=expression.length();

		for(int i=0;i<len;i++){

			t=expression.charAt(i);

			switch(t){

			case '-':

			case '+':if(!exp.empty()&& !exp.peek().equals("(") && !exp.peek().equals(")")){

				s=compute(exp.pop());

				num.push(s);

			} exp.push(String.valueOf(t));

			break;

			case '/':

			case '*':

				if(!exp.empty()&& exp.peek().equals("/")){

					s=compute(exp.pop());

					num.push(s);

				}else if(!exp.empty() && exp.peek().equals("*")){

					s=compute(exp.pop());

					num.push(s);

				}

				exp.push(String.valueOf(t));break;

			case '(':exp.push(String.valueOf(t));break;

			case ')':{

				while(!exp.peek().equals("(")){

					s=compute(exp.pop());

					num.push(s);

				}

				exp.pop();

				break;

			}

			case '=':{

				while(!exp.empty()){

					s=compute(exp.pop());

					num.push(s);

				}

				System.out.println(num.pop());

				break;

			}

			default:num.push(t-48);

		}

	}

}

	private int compute(String exp){

		int n2=num.pop();

		int n1=num.pop();

		switch(exp.charAt(0)){

		case '+':return n1+n2;

		case '-':return n1-n2;

		case '*':return n1*n2;

		case '/':return n1/n2;

		}

		return -1;

	}

	public static void main(String args[]){

		Calcu c=new Calcu();

		c.calculate();

	}

}