The necessity of 'showpoint' manipulator

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SamuelTangz
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Posts: 4
Joined: Wed Jul 31, 2013 11:09 am

The necessity of 'showpoint' manipulator

Post by SamuelTangz » Sat Aug 10, 2013 12:35 pm

Hi,

I am a novice on C++ programming, and recently I am studying decimal representations.
Eventually I found the following code:

Code: Select all

#include<iostream>
#include<iomanip>
using namespace std;
int main(void){
 float x = 1;
 cout << fixed << showpoint << setprecision(4);
 cout << x;
 return 0;
}
And the output is, 0.0000.

I found that the purpose of 'showpoint' is to display the decimal point if it is a floating-point number, no matter the decimal part exists or not.
However, the 'fixed' manipulator does the same thing (apparently for me).

Code: Select all

#include<iostream>
#include<iomanip>
using namespace std;
int main(void){
 float x = 1;
 cout << fixed << setprecision(4);
 cout << x;
 return 0;
}
And the output for this code segment is also 1.0000.

Is 'showpoint' necessary in the above code?
What are the differences between these codes?

Many thanks,
Samuel

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