| Initial Comments |
/* Formatting and <iomanip.h>
file: 4ex3.cpp (or used as 4ex3.appended)
FALL 1998
___________________________________
Jacob Y. Kazakia jyk0
September 28, 1998
Programming example 3 of week 4
Recitation Instructor: J.Y.Kazakia
Recitation Section 01
___________________________________
Purpose: This program reads three numbers a, b, and c through
the keyboard and outputs them on the screen in various
FIXED formats.
DOUBLE PRECISION IS USED ( 8 bytes per number )
Algorithm: The functions: setiosflags, setw, setprecision are
used to format the output
ios:: fixed
ios:: scientific
ios:: showpoint
*/
#include <iostream.h>
#include <iomanip.h>
void main()
{
// variables are typed and defined
double a,b,c; // the three numbers
cout<<" \n\n Please enter 3 numbers \n a = ";
cin>>a;
cout<<"\n b = ";
cin>>b;
cout<<"\n c = ";
cin>>c;
|
| Since the function setiosflags
is sent to cout, Data directed
to the default output will be in fixed form |
// Output everything in fixed point form
cout<<setiosflags( ios::fixed );
//***********************************************************
|
Precision is set to 14 digits after the decimal point (this
makes sense because the variables are declared double).
A string of numbers is sent out so that we can easily examine the location
of data in the output.
The width is set to 20 for each one of the three numbers a, b, and c. |
cout<<"\n\n\n With precision 14 and width 20 \n";
cout<<setprecision(14);
cout<<"\n 1 2 3 4 5 \n";
cout<<"12345678901234567890123456789012345678901234567890 \n" ;
cout<< setw(20)<<a <<setw(20)<< b <<setw(20)<< c ;
//***********************************************************
|
Precision is set to 5 digits after the decimal point.
A string of numbers is sent out so that we can easily examine the location
of data in the output.
The width is set to 10 for each one of the three numbers a, b, and c. |
cout<<"\n\n\n With precision 5 and width 10 \n" ;
cout<<setprecision(5);
cout<<"\n 1 2 3 4 5 \n";
cout<<"12345678901234567890123456789012345678901234567890 \n" ;
cout<< setw(10)<<a <<setw(10)<< b <<setw(10)<< c ;
//***********************************************************
|
| |
cout<<endl<<endl;
cout<<" enter e (exit) to terminate the program....";
char w;
cin>>w;
}
/* THESE ARE SOME OF THE OUTPUTS
|
The first number, when entered as fixed, needs 13 significant
digits. Since it is declared as double, all this detail is maintained
and reflected at the output.
Notice that 14 digits after the decimal point are shown even if they are
zero.
The numbers are placed into the 20 slot openings with right justification. |
Please enter 3 numbers
a = 12.00000034567
b = -13.45678
c = 0.00000000012345678
With precision 14 and width 20
1 2 3 4 5
12345678901234567890123456789012345678901234567890
12.00000034567000 -13.45678000000000 0.00000000012346
|
Note that the third number is outputted as zero.
How can we see the detail in a short span of spaces? |
With precision 5 and width 10
1 2 3 4 5
12345678901234567890123456789012345678901234567890
12.00000 -13.45678 0.00000
enter e (exit) to terminate the program....
*************************************************************
|
Same story here for a different set of numbers.
Try to understand why the output looks as it does. |
*************************************************************
Please enter 3 numbers
a = 12.000000001234567891234
b = -3.0000000345
c = 0.10101010202022222222345
With precision 14 and width 20
1 2 3 4 5
12345678901234567890123456789012345678901234567890
12.00000000123457 -3.00000003450000 0.10101010202022
With precision 5 and width 10
1 2 3 4 5
12345678901234567890123456789012345678901234567890
12.00000 -3.00000 0.10101
enter e (exit) to terminate the program.... */
|
© 2001 J.Y. Kazakia. All rights reserved