1. 문제

2. 코드

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        int lineCnt = 1;
        int result = n;
        String s = "";

	// s 가 = 이 아닌 경우 반복
        while (!s.equals("=")) {
            lineCnt++;
            if (lineCnt % 2 != 0) {
                n = Integer.parseInt(br.readLine());

                switch(s) {
                    case "+":
                        result += n;
                        break;
                    case "-":
                        result -= n;
                        break;
                    case "*":
                        result *= n;
                        break;
                    case "/":
                        result /= n;
                        break;
                    default:
                        break;
                }
            } else {
                s = br.readLine();
            }
        }

        System.out.println(result);
    }
}

3. 링크

https://www.acmicpc.net/problem/5613