Output FormattingNo, I don't want 6 digits…

Standard Behavior

• Rules for printing decimals:– No decimal point:

1.0000 prints as 1– No trailing zeros:

1.5000 prints as 1.5– Use 6 digits :

123.43289 prints as 123.433– Scientific notation for large/small numbers:

1234567890.0 prints as 1.23457e+09

Output and Formatting Output

• cout accepts expressions or manipulators

– if expression , value is printed– if manipulator, output format is modified

cout options

• Manipulators : special values that tell cout how to do its job

cout << "Hey – show 2 decimal places" << 5.1234;

• Basic manipulator : endl• Others in iomanip library

#include <iomanip>

showpoint Manipulator

• showpoint forces output to show the decimal point and trailing zeros

• Example:cout << 15.0 << " " << showpoint << 15.0 << " ";

cout << 4.0 << endl;

15 15.0000 4.0000

Persistent

fixed Manipulator

• Doubles output in floating-point format:cout << 1231234234.23123123 << endl;1.23123e+009

• fixed forces output as fixed decimal points:cout << fixed;cout << 1231234234.23123123 << endl;1231234234.23123123

Persistent

fixed Manipulator

• scientific manipulator– Return to floating point format

cout << fixed;cout << 1231234234.23123123 << endl;1231234234.23123123cout << scientific;cout << 1231234234.23123123 << endl;1.23123e+009

Persistent

setprecision Manipulator

• setprecision(n)

– Number of decimal places before value is rounded

cout << fixed << setprecision(2);cout << 15.128234 << " "; cout << 435.3 << endl;

15.13 435.30

Persistent

setw

• setw(x)– Makes next expression take up at least x columns

• Adds spaces to left

cout << 5 << setw(5) << 12 << endl;5 12......

– Longer expressions not affected:cout << 5 << setw(2) << 12123;

512123......

setw

• setw(x)– Applies only to next expressioncout << setw(6) << 12 << 12; 1212........

cout << setw(6) << 12

<< setw(6) << 12; 12 12............

NOT Persistent

Additional Output Formatting Tools

• setfill(char)– What char to use instead of spaces to fill columns

• left and right manipulators– Which side to justify text

cout << left << setfill('*');

cout << setw(5) << 12 << 10;

12***10

Persistent

Goal

• Read in 2 numbers – numerator, denominator• Print something like this:

Enter numbers: 2 3

Numerator/Denominator Decimal Value

2/3 0.67

Goal

• Visualize spaces:Enter numbers: 2 3

Numerator/Denominator..Decimal Value

........2/3............0.67

• Break into pieces:........2 : right, width of 9

3.......... : left, width of 11

0.67 : 2 decimal places, fixed

Finished Program