setw( ) I almost understand, but I'm getting some weird results.

I'm using TutorialsPoint C++ examples to figure some things out, and though I've figured out what I can, I cannot tell why my output isn't going the way I want with the setw() "method"?

As you can see in the code I've c/p'ed, I'm trying to get the Book info to align with the first line of information after "Book 1:"

I've kept the Book 2 section of the output as is in case I want to start over, never mind it.

MY question is, the setw() only responds after I put in a high enough value. For the first setw() value it wouldn't begin moving "Book1.author" until the value was 11 or higher. The second setw() value didn't begin moving "Book1.subject" until the value was 28 or higher, but as you can see, "Book1.book_id" responded properly to setw(15). It didn't follow a trend that I can see, so I'm at a loss as to where it is getting it's marching orders outside of my setw() values.

Also, thanks for any help. I'm positive my lingo is off, please forgive me. As I progress, the questions will be worded with the proper terminology.

Code:

---

#include "stdafx.h"
#include <iostream>
#include <cstring>
#include <iomanip>
 
using std::cout;
using std::cin;
using std::endl;
using std::setw;
 
struct Books
{
  char  title[50];
  char  author[50];
  char  subject[200];
  int  book_id;
};
 
int main( )
{
  struct Books Book1;        // Declare Book1 of type Book
  struct Books Book2;        // Declare Book2 of type Book
 
  // book 1 specification
  strcpy( Book1.title, "Learn C++ Programming");
  strcpy( Book1.author, "Chand Miyan");
  strcpy( Book1.subject, "a huge ****ing subject line");
  Book1.book_id = 6495407;

  // book 2 specification
  strcpy( Book2.title, "Telecom Billing");
  strcpy( Book2.author, "Yakit Singha");
  strcpy( Book2.subject, "Telecom");
  Book2.book_id = 6495700;
 
  // Print Book1 info
  cout << "Book 1: " << Book1.title << endl;
  cout << setw(19) << Book1.author << endl;
  cout << setw(45) << Book1.subject << endl;
  cout << setw(15) << Book1.book_id << endl;

  // Print Book2 info
  cout << "Book 2 title : " << Book2.title << endl;
  cout << "Book 2 author : " << Book2.author << endl;
  cout << "Book 2 subject : " << Book2.subject << endl;
  cout << "Book 2 id : " << Book2.book_id << endl;

  return 0;
}

---

Thanks

setw() sets the width for the next element in the stream ie the number of character positions in which the value should be output. If the value to be output is narrower than the specified width then fill characters are inserted as padding. A value wider than the designated width will not be truncated. If you want the book info to align, try something like this

Code:

---

        // Print Book1 info
        cout << "Book 1: " << Book1.title << endl;
        cout << setw(8) << " " << Book1.author << endl;
        cout << setw(8) << " " << Book1.subject << endl;
        cout << setw(8) << " " << Book1.book_id << endl;

---

You could also use tabs like this

Code:

---

        // Print Book1 info
        cout << "Book 1: " << Book1.title << endl;
        cout << "\t" << Book1.author << endl;
        cout << "\t" << Book1.subject << endl;
        cout << "\t" << Book1.book_id << endl;

---

I would also suggest that you use type string in your struct rather than fixed size char arrays. See http://www.cplusplus.com/reference/string/

Thanks. I got it.

I saw it used here:

Code:

---

// output each array element's value                     
  for ( int j = 0; j < 10; j++ )
  {
      cout << setw( 7 )<< j << setw( 13 ) << n[ j ] << endl;
  }
 
  return 0;
}

---

I didn't see the << "[insert character here]" <<... and so on; not in simple terms at least. Matter of fact, even after seeing your use of it in your example, it only clicked a couple hours later that the << " " << designates the character to use in the setw() execution.

So, I understand that you have initialize(correct term?) setw() with the desired character that is going to repeated for the length of the value.

Awesome. Thanks 2kaud.

Also, in these examples I'm copying and pasting, I'm simply working on the bits that apply to my query. I have not heard the part about type string in structs yet, I'll make a note.

Though I've heard of the "\t" sequence, I didn't even think to try it here. I'm newer than new.

Again, thanks.

I became a member here when all of my questions were closed nearly immediately on Stack. Thanks for the direct advice. If I can improve my placement within the forum of the threads I start, I will. And as always, I do a pretty exhaustive search of the terminology I'm familiar with before starting threads.

Code:

---

cout << setw( 7 )<< j << setw( 13 ) << n[ j ] << endl;

---

what this does is output j in width of 7 and n[j] in a width of 13

Quote:

---

<< designates the character to use in the setw() execution.

---

In this context << is the stream insertion operator. It inserts into the specified output stream (cout in this case) the value of what follows to its right or sets formatting as specified by an io manipulator.

setw(n) sets the field width for the following output where n is the required minimum width of the following value. See http://www.cplusplus.com/reference/iomanip/

There are also other format manipulators that can be used. See http://www.cplusplus.com/reference/ios/


/t is an example of an escape sequence. There are several that can be used. See https://msdn.microsoft.com/en-us/library/h21280bw.aspx