Formatting Output - fixed, showpoint, setprecision
Summary
TLDRThis video demonstrates the use of format manipulators in a simple C++ program. It begins with displaying values of two variables, x and y, then introduces the iomanip library for formatting. The 'fixed' and 'showpoint' manipulators ensure decimal points are always shown. 'Setprecision' is used to control the number of decimal places displayed, which is demonstrated by adjusting precision levels. The video also shows that 'setprecision' affects floating-point values but not integers. The explanation is clear and includes running the program to illustrate the effects of these format manipulators.
Takeaways
- 📚 The script demonstrates the use of format manipulators in a simple program.
- 🔢 Two variables, x and y, are defined with values 123.456 and 987.654, respectively.
- 💻 The program displays the values of x and y using cout.
- 📘 To use format manipulators, the iomanip library is included in the program.
- 🔧 Adding 'fixed' and 'showpoint' ensures values are displayed in fixed notation with decimal points.
- 🔍 'setprecision' is used to control the number of decimal places displayed.
- ✏️ Setting precision to 2 rounds the value of x to 123.46 and y remains 987.65.
- 🔄 Precision can be changed at any point in the program.
- 🔢 Setting precision to 1 rounds x to 123.5 and y to 987.7.
- ➖ Setting precision to 0 displays the decimal point without any decimal places.
- 🔢 Adding an integer variable z with a value of 10 shows that 'setprecision' does not affect integers.
Q & A
What are the variables used in the example program?
-The variables used in the example program are x and y.
What does the program initially display?
-The program initially displays the value of x and y, which are 123.456 and 987.654 respectively.
What library needs to be included to use format manipulators?
-The IO manip library needs to be included to use format manipulators.
Why is the 'fixed' manipulator used in the program?
-The 'fixed' manipulator is used to ensure that the values are displayed in fixed notation, avoiding exponential notation.
What is the purpose of the 'showpoint' manipulator?
-The 'showpoint' manipulator ensures that the decimal point is always displayed, even for values like 4.0.
How does 'setprecision' affect the output?
-'setprecision' sets the number of decimal places for the output. For example, setting precision to 2 will display two places after the decimal.
What happens when the precision is set to 2 for the initial values of x and y?
-When the precision is set to 2, the value of x is rounded to 123.46 and the value of y is displayed as 987.65.
Can the precision be changed at different points in the program?
-Yes, the precision can be changed at different points in the program to affect subsequent outputs.
What is the output when the precision is set to 1 for y?
-When the precision is set to 1 for y, it is displayed as 987.7.
Does 'setprecision' affect integer values?
-'setprecision' does not affect integer values; it only works with floating-point values.
What is the value of the integer variable z in the program?
-The value of the integer variable z in the program is 10.
Outlines
🔧 Demonstrating Format Manipulators
This paragraph introduces a simple program to demonstrate format manipulators in C++. It starts with defining two variables, x and y, and prints their values. The program then introduces the iomanip library to include format manipulators, explaining that each library must be on separate lines without semicolons. The fixed and showpoint manipulators are used to ensure values display in fixed notation and show decimal points. The precision is set to ensure only two decimal places are shown. The program also demonstrates changing the precision during runtime and explains that setprecision does not affect integers.
Mindmap
Keywords
💡format manipulators
💡fixed
💡showpoint
💡setprecision
💡iostream
💡iomanip
💡variable
💡floating-point numbers
💡integer
💡precision
Highlights
Introduction to format manipulators in programming
Demonstration of a simple program with variables x and y
Displaying the values of x and y using cout
Inclusion of the IO manip library for format manipulators
Explanation of the importance of separating libraries in preprocessor directives
Use of fixed and show point to control the display of floating-point values
Fixed notation prevents values from being displayed in exponential form
Show point ensures the decimal point is displayed in values
Impact of set precision on the number of decimal places displayed
Example of setting precision to two decimal places
Demonstration of rounding behavior with set precision
Changing precision during the program to one decimal place
Observation of precision effect on integer values
Inclusion of the integer manipulator and its effect on variable Z
Demonstration of set precision having no effect on integers
Final display of variable Z with no decimal point due to integer type
Transcripts
in this example I'm going to demonstrate
format manipulators here's a very simple
program I have two variables x and y you
can see the values stored in there I'm
going to see out X is it's going to
display the value of the variable X and
down to the next line and display Y is
the value of the variable Y and the
program is going to end here's what it
looks like
okay X is one two three point four five
six y is nine eight seven point six five
four okay now I'm going to add some
format manipulators when you have any
format manipulators you need to add a
new library in your program so I'm going
to include
IO manip that's the name of the library
notice you can have more than one
library up here if you do each library
has to be on different lines right
separate lines never any semicolons at
the end of these preprocessor directives
and the order is not important now most
of the time what programmers do is right
before there see out statements they'll
put this line in here
okay and what fixed in show point two is
they will ensure that the values that
get displayed are first of all in a
fixed notation that means you won't see
any values with an exponent in them like
e to the plus O to the values that I'm
using by default won't go into that
exponential notation but if you use
values with more significant digits or
larger values they might so you always
want to use fixed and show point make
sure that your decimal point displays if
you have a value like four point zero it
will only display for by default unless
you have show point in there so by
putting this one line right prior to
your C out statements where you display
your results it'll make sure that that's
an effect for the rest of the program
next I'm going to demonstrate set
precision
so I'm going to set the precision to two
just because that was my choice and set
precision will set the number of decimal
places for everything from this point on
number of decimal places will be two
right two places after the decimal
notice our values one two three point
four five six and nine eight seven point
six five four let's run this program and
see what happens now
notice two places after the decimal the
first value one two three point four was
rounded up right because it was four or
five six and the second value point six
five was left alone because the value
after the five is four so it's not good
around that value up you could change
the precision at any point in your
program I'm going to come down here I'm
going to set my precision
to
one
and I'm going to run it again so when x
comes out it should have a precision of
two and then down here this will change
Y to a precision of one
and you'll see that's exactly what
happened okay let's just see what
happens when we change your position to
zero
all right you'll see this you get the
decimal point but you don't get the zero
okay and one last thing I'm going to do
is I'm going to put it integer in here
and Z is assigned a value of 10 and at
the end of my program I'll display Z as
well
and let's see what happens now keep in
mind Z is an integer
notice what happens with Z step
precision has no effect on integer it
only works with floating point values
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