1. Formatting Screen Input/Output
INFSY 307
C++
Formatting Screen Input/Output

2. Format Flags
setf (ios::<flagname>)
unsetf(ios::<a flag>);
common flagnames:
fixed
left
showpoint
right

3. Formatting flags Fixed - ensures fixed format, i.e no
scientific notation or problems with fixed
formats.
showpoint - ensures that decimal points and trailing zeros are displayed
left – left adjusts output
right - right adjusts output

4. Examples: Note: Important to unset flag! cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.setf(ios::fixed | ios::showpoint);
cout.unsetf(ios::right);
Note: Important to unset flag!

5. Formatting Manipulator
Manipulators are placed after the insertion operator:
setprecision (2); - two decimal digits are output
setw (4); - describes width of next field
- cout.width (4); or cout.precision (2) is an
alternative
Note: cout << is required
#include <iomanip.h> is required

6. Formatting Flags and Manipulators
Examples
cout<< setprecision (2)<<“Value is: “<<10.5;
cout<<setw(7)<<value1<<setw(5)<<value2<<endl;
cout<< setw (4)<<“abc”; (note only for next variable)
cout.precision (4);
cout.width (10);
(note: width is only for next next variable
precisision remains set)

7. Formatting Rules Flags and most manipulators remain set until reset
When a field is too small, C++ will adjust it and print the
true value of a number
3. When a string variable is output, the field width will be
filled with whatever is in memory unless a ‘\0’ is found.
‘\0’ is referred to as the NULL character
and is a special character similar to ‘\n’
4. Extra bytes are padded with spaces.