Add up outputs/strings in a loop

Question

How to add up different strings in a loop?

My Example:

Having a Stern–Brocot tree path finder. The only problem is that it should give output as one line. Full code:

import java.io.*;
import java.util.*;
public class Main {
  public static void main(String[] args) {
    double p, q;
    Scanner in = new Scanner(System.in);
    int[] vars = new int[2];
    for(int i = 0; i < vars.length; i++)
      vars[i] = in.nextInt();
    p = vars[0];
    q = vars[1];

  double p1 = 0 ;
  double p2 = 1 ;

  double q1 = 1 ;
  double q2 = 0 ;
  while( p1+p2 != p  && q1+q2 != q )
  {
      if (( p1+p2 )/ (q1+q2 ) < p / q) 
      {
          System.out.println("R");
          p1 += p2;
          q1 += q2;
      } 
      else if( ( p1+p2 ) / ( q1+q2 ) > p/q )
      {
          System.out.println("L");
          p2 += p1;
          q2 += q1;
      }
    }
  }
}

The main part. The part i have to fix.

while( p1+p2 != p  && q1+q2 != q )
  {
      if (( p1+p2 )/ (q1+q2 ) < p / q) 
      {
          System.out.println("R");
          p1 += p2;
          q1 += q2;
      } 
      else if( ( p1+p2 ) / ( q1+q2 ) > p/q )
      {
          System.out.println("L");
          p2 += p1;
          q2 += q1;
      }
    }
  }

Problem: How could i make it like that, that each time it does the loop, it will add the answer to the full answer and after everything is done, it throws full answer in one line. Pretty much something like that:

answer = answer + ("R");
answer = answer + ("L");
System.out.println(answer);

kavi chapagain · Accepted Answer · 2017-12-03 11:19:27Z

1

Using System.out.print() instead of System.out.println() would work here, I guess.

answered Dec 3, 2017 at 11:19

kavi chapagain

343 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Sergey Kalinichenko · Accepted Answer · 2017-12-03 11:21:50Z

1

Use StringBuilder.

Make an instance of StringBuilder before the loop, and call append method repeatedly to construct the output string. Once you are done forming the result string, call toString to obtain and print the final result.

StringBuilder answerBuilder = new StringBuilder();
while( ... ) {
    ...
    answerBuilder.append("L");
    ...
    answerBuilder.append("R");
    ...
}
String answer = answerBuilder.toString();

An advantage of keeping a StringBuilder over printing-as-you-go approach is that you can go back and change the beginning or the middle of the string that you build before printing it.

answered Dec 3, 2017 at 11:21

Sergey Kalinichenko

729k85 gold badges1.2k silver badges1.6k bronze badges

Comments

Lalit Verma · Accepted Answer · 2017-12-03 11:22:47Z

1

If you want the answer at the last just use StringBuilder and append each string you display and at the end just show this StrigBuilder variable.

answered Dec 3, 2017 at 11:22

Lalit Verma

80211 silver badges25 bronze badges

Collectives™ on Stack Overflow

Add up outputs/strings in a loop

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related