Formatting Output

#include <iostream.h>
/************************************************
 File: format1.C
 An example illustrating the use of
 the setf() function to format output
************************************************/

int main()
{
     float y = 16.0011;
     // display using default settings
     cout << y << " hello" << "\n";

     // change format to scientific
     cout.setf(ios::scientific);
     cout << y << " hello" << "\n";

     // change format to decimal, show positive sign, show
     // fixed format
     cout.unsetf(ios::scientific);
     cout.setf(ios::showpos | ios::fixed);
     cout << y << " hello" << "\n";
     
     // reset format to eliminate the positive sign
     cout.unsetf(ios::showpos);
     cout << y << " hello" << "\n";

     // show the status of format flags
     long z = cout.flags();
     cout << "format flags: " << z << "\n";

     exit(0);
}

Output:

16.0011 hello
1.600110e+01 hello
+16.001101 hello
16.001101 hello
format flags: 36865

#include <iostream.h>
/**********************************************
 File: format2.C
 An example illustrating the use of width()
 precision(), and fill() functions for 
 formatting output
**********************************************/

int main()
{
     cout.width(10); // set minimum field width
     cout << "hello" << "\n";

     cout.fill('*'); // set fill character
     cout.width(10); // set minimum field width
     cout << "hello" << "\n"; // right justify by default

     cout.setf(ios::left); // set left justification
     cout.width(10); // set minimum field width
     cout << "hello" << "\n"; // left justified output

     double d = 123.234567;
     cout.setf(ios::fixed); // set fixed numeric format
     cout.width(12); // set minimum field width
     cout << d << "\n"; // default precision of 6 digits after the decimal

     cout.width(12); // set minimum field width
     cout.precision(5); // set precision to 5 digits
     cout << d << "\n"; // 5 digits precision after the decimal

     exit(0);
}

Output:

     hello
*****hello
hello*****
123.234567**
123.23457***

#include <iostream.h>
/******************************************************
 File: format3.C
 Create a table of float values and and their squares
 using the I/O format flags
******************************************************/

int main()
{
     double x;
     cout.setf(ios::fixed);
     cout.precision(3);
     cout << "      x        x^2\n\n";

     for (x = 2.2 ; x <= 20.2 ; x++) {
          cout.width(7);
          cout << x << "    ";
          cout.width(7);
          cout << x*x << '\n';
     }
     exit(0);
}

Output:

      x        x^2

  2.200      4.840
  3.200     10.240
  4.200     17.640
  5.200     27.040
  6.200     38.440
  7.200     51.840
  8.200     67.240
  9.200     84.640
 10.200    104.040
 11.200    125.440
 12.200    148.840
 13.200    174.240
 14.200    201.640
 15.200    231.040
 16.200    262.440
 17.200    295.840
 18.200    331.240
 19.200    368.640
 20.200    408.040

#include <iostream.h>
#include <iomanip.h>
/***************************************************
 File: format4.C
 Create a table of float values and their squares
 using the I/O manipulators
***************************************************/

int main()
{
     double x;
     cout.setf(ios::fixed);
     cout << setprecision(3);
     cout << "      x        x^2\n\n";

     for (x = 2.2 ; x <= 20.2 ; x++) {
          cout << setw(7) << x << "    ";
          cout << setw(7) << x*x << endl;
     }
     exit(0);
}

Output:
     
      x        x^2

  2.200      4.840
  3.200     10.240
  4.200     17.640
  5.200     27.040
  6.200     38.440
  7.200     51.840
  8.200     67.240
  9.200     84.640
 10.200    104.040
 11.200    125.440
 12.200    148.840
 13.200    174.240
 14.200    201.640
 15.200    231.040
 16.200    262.440
 17.200    295.840
 18.200    331.240
 19.200    368.640
 20.200    408.040