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| Initial Comments |
/* Formatting and <iomanip.h>
file: 4ex1.cpp(or used as 4ex1.appended)
FALL 1998
___________________________________
Jacob Y. Kazakia jyk0
September 28, 1998
Programming example 1 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.
Algorithm: Uses the functions: setiosflags, setw, setprecision
to format output
ios:: fixed
ios:: scientific
ios:: showpoint
*/
#include <iostream.h>
#include <iomanip.h>
void main()
{
// variables are typed and defined
float 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;
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| 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 );
//***********************************************************
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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 20 for each one of the three numbers a, b, and c. |
cout<<"\n\n\n With precision 5 and width 20 \n";
cout<<setprecision(5);
cout<<"\n 1 2 3 4 5 \n";
cout<<"12345678901234567890123456789012345678901234567890 \n" ;
cout<< setw(20)<<a <<setw(20)<< b <<setw(20)<< c ;
//***********************************************************
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Precision is set to 3 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 3 and width 10 \n" ;
cout<<setprecision(3);
cout<<"\n 1 2 3 4 5 \n";
cout<<"12345678901234567890123456789012345678901234567890 \n" ;
cout<< setw(10)<<a <<setw(10)<< b <<setw(10)<< c ;
//***********************************************************
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| |
cout<<endl<<endl;
cout<<" enter e (exit) to terminate the program....";
char w;
cin>>w;
}
/* THESE ARE SOME OF THE OUTPUTS
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The third number is entered using 13 significant digits. You will notice
that its output has only 9 nonzero digits, the last two being incorrect.
Why?
( c is declared as float)
Notice that 5 digits after the decimal point are shown even if they are
zero.
The numbers are placed into the 20 slot openings with right justification.
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Please enter 3 numbers
a = 123
b = 0.67895
c = 123456789.0987
With precision 5 and width 20
1 2 3 4 5
12345678901234567890123456789012345678901234567890
123.00000 0.67895 123456792.00000
************************************************************
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Note that the third number is longer than 10 places. Two things
happen:
a) there is no distance between the second and third
b) the 10 place space for the third number is automatically increased
to 13.
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With precision 3 and width 10
1 2 3 4 5
12345678901234567890123456789012345678901234567890
123.000 0.679123456792.000
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Same story here for a different set of numbers.
Try to understand why the output looks as it does. |
************************************************************
Please enter 3 numbers
a = 12.789
b = 0.0000023
c = -456.78967
With precision 5 and width 20
1 2 3 4 5
12345678901234567890123456789012345678901234567890
12.78900 0.00000 -456.78967
With precision 3 and width 10
1 2 3 4 5
12345678901234567890123456789012345678901234567890
12.789 0.000 -456.790
enter e (exit) to terminate the program.... */
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© 2001 J.Y. Kazakia. All rights reserved