學校作業[求助]急~拜託~作業一下3題又要考期中考

public class Test{

  public static void main(String[] args) throws Exception{
    Test t = new Test();

    java.io.BufferedReader input = new java.io.BufferedReader(new java.io.InputStreamReader(System.in));

    while(true){
      System.out.print("Please enter a number(1~50,0 for exit): ");
      String stTemp = input.readLine();
      int iTemp = 0;
      try{
        iTemp = Integer.parseInt(stTemp);
      }
      catch(Exception e){
        System.out.println("parse number error, plz enter a valid number.");
        break;
      }

      if(iTemp==0){
        System.out.print("exit.");
        break;
      }
      else if(iTemp<0){
        System.out.println("negative number!");
      }
      else if(iTemp>50){
        System.out.println("number > 50.");
      }
      else{
        for(int i=1;i<=iTemp;i++){
          System.out.println(""+i+"*"+i+"="+(i*i));
        }
      }
    }
  }


}