1. Chapter 3 L7

2. Formatting output L7 Manipulator (flags) setprecision showpoints
setleft
setright
setw stream

3. 3.8 Formatting Output
Can control how output displays for numeric, string data:
size
position
number of digits
Requires iomanip header file

4. Precision and formatted output
How many values appear after and before the decimal point ??
cout<< setiosflags(ios::fixed | ios :: showpoint)<< setprecision (2); Or
cout<< fixed << showpoint<< setprecision (2);
Defined in the <iomanip.h> library

5. #include <iostream>
#include <iomanip>
Using namespase std;
int main() {
float x;
cout << "x = ";
cin>> x;
cout << setiosflags (ios :: fixed | ios :: showpoint | ios:: left)<<setprecision(2);
// or
// cout << fixed << showpoint<< left <<setprecision(2);
cout << x ;
Return 0; }
Input
Outout

6. Stream Manipulators Used to control features of an output field
Some affect just the next value displayed:
setw(x): print in a field at least x spaces wide. Use more spaces if field is not wide enough
Some affect values until changed again:
fixed: use decimal notation for floating-point values
setprecision(x): when used with fixed, prints floating-point value using x digits after the decimal. Without fixed, prints floating-point value using x significant digits // show an example of both Mix18.cpp
showpoint: always print decimal for floating-point values )

7. Manipulator Examples const double e = 2.718;
cout << setw(8) << e; // in a
// field 8 wide
cout << setprecision(2);
cout << e; // 2.7
cout << fixed<<setprecision(2);
cout << e; // 2.72
double price = 25.0, discount = 0.6;
cout << fixed << setprecision(2);
cout << price * discount; // 15.00

8. Formatting output stream manipulator setw()
int Numb1 = 100, Numb2 = 200, Numb3 = 300;
cout << Numb1 <<Numb2 <<Numb3;
Gives us
BUT:
cout << setw(5 )<<Numb1<<setw(7) << Numb2<<setw(5)<<Numb3
SS100SSSS200SS300

9. The left and right Manipulators “right is the default”
float Miles = ;
cout << setw(12)<<Miles;
SSSSS
cout << setiosflags (ios::left) <<setw(12) << Miles;
cout<<left<<setw(12)<<Miles;
SSSSS
cout << setiosflags(ios::right) << setw(12) << Miles;

10. Formatting output setprecision manipulator setprecision()
float Num1 = ;
cout << Num1;
cout << fixed<<setprecision(4)<<Num1;
cout << fixed<<setprecision(5)<<Num1;
cout <<fixed<<setprecision(6)<<Num1;

11. BIG difference between set precision in Turbo and .net compilers
Look at table 3-11 page 109
Compare with the outcome of this program.
#include<iostream.h>
#include<iomanip.h>
int main() {
float Num1 = ;
cout<< setiosflags(ios::fixed)<< setprecision (3) << Num1;
return 0; }
Output on turbo and DEV, 28.9 on dot net !!

12. Formatting output setprecision manipulator setprecision()
float Num1 = ;
cout << setprecision(2)<<Num1;
2.1e+03
cout << setprecision(12)<<Num1;
!!!!

13. Formatting output manipulator setprecision + fixed()
Forces cout to print the digits in fixed point notation or decimal.
float Num1 = ;
cout<< setiosflags(ios::fixed)<< setprecision (2) << Num1;
210.12
cout<< setiosflags(ios::fixed)<< setprecision (4) << Num1;

14. Formatting output manipulator showpoint()
Forces cout to display the trailing zeros.
float Num1 = ;
cout << Num1;
210
cout<< setiosflags(ios :: showpoint)<< Num1;
NOTE:
Cout <<setprecision(2)<<showpoint;
// works for .net AND FOR DEV but not for Turbo

15. showpoint and setprecision
float Num1 = ;
cout<< setprecision(6)<< Num1;
210 // would not show the 0000
cout setsettiosflags (ios::showpoint)
<<setprecision(6)<< Num1;

16. showpoint and setprecision
causes the decimal points and trailing zeros to be displayed EVEN if there is no fractional part
float Num1 = 210 ;
cout<< setiosflags(ios :: showpoint) << setprecision(6) << Num1;

17. The fill( ) function cout.fill (‘x’)
Changes the fill character, whicjh is by default a space to be something else, ie x.
float Miles = ;
cout << setiosflags(ios :: right) << setw(12) << Miles;
SSSSS
cout.fill('x');
cout << setiosflags(ios :: right) << setw(12)
<<Miles;
xxxxx

18. setw() and strings cout<<“I Love C++ Programming”;
Will give you:
I Love C++ Programming
cout<<setw(22)<<“I Love C++ Programming”;
Would give you the same, as long as its 22, or less.
cout<<setw(30)<<“I Love C++ Programming”;
SSSSSSSSI Love C++ Programming // right justified

19. When the size of the setw() less or = the size of the string
// This program demonstrates the setw manipulator being
// used with values of various data types.
#include <iostream>
#include <iomanip>
using namespace std;
int main() {
int intValue = 3928;
double doubleValue = 91.5;
const int ARRAY_SIZE = 14;
char cStringValue[ARRAY_SIZE] = "John J. Smith";
cout << "(" << setw(5) << intValue << ")" << endl;
cout << "(" << setw(8) << doubleValue << ")" << endl;
cout << "(" << setw(16) << cStringValue << ")" << endl;
// cout << "(" << setw(16) << cStringValue << ")" << endl
system("pause");
return 0; }

20. Program example// notice the changes from yours
// we will run this program to demonstrate how flags work
// if statments and loops wil be covered soon
#include <iostream>
#include <iomanip>
using namespace std;
int main() {
float weight;
int i;
for (i = 0; i < 6; i++)
cout<< fixed << showpoint<< setprecision (2);
//cout<< setiosflags(ios :: fixed |ios :: showpoint)<< setprecision (2);
cout << " \n enter weight \n" ;
cin >> weight;
if (weight > 150 )
cout << weight << setw(3)<< " over weight ";
else if (weight > 100 && weight < 150)
cout<< weight<<setw(3) << " no risk ";
else
cout << weight<<setw(3)<<" too thin "; }
return 0;