27. COM and DHTML

	Chapter 18 - Complete I/O in C++
	Visual C++ 6: The Complete Reference
	Chris H. Pappas and William H. Murray, III

Copyright 1998 The McGraw-Hill Companies

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	Formatting Output

	The next example continues the development of C++ formatted output initially introduced in Chapter 12. The first program demonstrates how to print a table of factorials using long doubles with the default right justification:

	// //  fact1.cpp //  A C++ program that prints a table of //  factorials for the numbers from 1 to 25. //  Program uses the long double type. //  Formatting includes precision, width and fixed //  with default of right justification when printing. //  Copyright (c) Chris H. Pappas and William H. Murray, 1998 // #include <iostream.h> #include <iomanip.h>

	main( ) {  long double number,factorial;  number=1.0;  factorial=1.0;  cout.precision(0);           // no decimal place  cout.setf(ios::fixed);       // use fixed format  for(int i=0;i<25;i++) {    factorial*=number;    number=number+1.0;    cout.width(30);            // width of 30 characters    cout << factorial << endl;  }  return (0); }

	The precision( ), width( ), and setf( ) class members functions were repeated in the loop. The output from the program takes on the following form:

	1                         2                         6                        24                       120                       720                      5040                     40320                    362880                   3628800                  39916800                 479001600                6227020800               87178291200             1307674368000            20922789888000           355687428096000          6402373705728000        121645100408832000       2432902008176640000      51090942171709440000    1124000727777607680000   25852016738884976640000  620448401733239439360000 15511210043330985984000000

	The next program/output pair demonstrates how to vary output column width and override the default right justification:

	// //  fact2.cpp //  A C++ program that prints a table of //  factorials for the numbers from 1 to 15. //  Program uses the long double type. //  Formatting includes precision, width, alignment, //  and format of large numbers. //  Copyright (c) Chris H. Pappas and William H. Murray, 1998 // #include <iostream.h> #include <iomanip.h> main( ) {  long double number,factorial;  number=1.0;  factorial=1.0;  cout.precision(0);           // no decimal point  cout.setf(ios::left);        // left justify numbers  cout.setf(ios::fixed);       // use fixed format

	for(int i=0;i<25;i++) {    factorial*=number;    number=number+1.0;    cout.width(30);            // width of 30 characters    cout << factorial << endl;  }  return (0); }

	The left-justified output takes on the following form:

	1                              2                              6                              24                             120                            720                            5040                           40320                          362880                         3628800                        39916800                       479001600                      6227020800                     87178291200                    1307674368000                  20922789888000                 355687428096000                6402373705728000               121645100408832000             2432902008176640000            51090942171709440000           1124000727777607680000         25852016738884976640000        620448401733239439360000       15511210043330985984000000

	The next example prints out a table of numbers, their squares, and their square roots. The program demonstrates how easy it is to align columns, pad with blanks, fill spaces with zeros, and control numeric precision in C++.

	// //  sqrt.cpp //  A C++ program that prints a table of //  numbers, squares, and square roots for the //  numbers from 1 to 15. Program uses the type //  double. Formatting aligns columns, pads blank //  spaces with ‘0’ character, and controls //  precision of answer. //  Copyright (c) Chris H. Pappas and William H. Murray, 1998 // #include <iostream.h> #include <iomanip.h> #include <math.h> main( ) {  double number,square,sqroot;

	cout << “num\t” << “square\t\t” << “square root\n”;  cout << “____________________________________\n”;  number=1.0;  cout.setf(ios::fixed);        // use fixed format  for(int i=1;i<16;i++) {    square=number*number;       // find square    sqroot=sqrt(number);        // find square root    cout.fill(‘0’);             // fill blanks with zeros    cout.width(2);              // column 2 characters wide    cout.precision(0);          // no decimal place    cout << number << “\t”;    cout.width(6);              // column 6 characters wide    cout.precision(1);          // print 1 decimal place    cout << square << “\t\t”;

	cout.width(8);              // column 8 characters wide    cout.precision(6);          // print 6 decimal places    cout << sqroot << endl;    number+=1.0;  }  return (0); }

	The formatted output takes on the following form:

	num     square           square root ____________________________________ 01      0001.0            1.000000 02      0004.0            1.414214 03      0009.0            1.732051 04      0016.0            2.000000 05      0025.0            2.236068 06      0036.0            2.449490 07      0049.0            2.645751 08      0064.0            2.828427 09      0081.0            3.000000 10      0100.0            3.162278 11      0121.0            3.316625 12      0144.0            3.464102 13      0169.0            3.605551 14      0196.0            3.741657 15      0225.0            3.872983

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